COP888GD 8-Bit CMOS ROM Based Microcontrollers with 16k Memory and 8-Channel A/D General Description The COP888GD ROM based microcontrollers are highly integrated COP8™ Feature core devices with 16k memory and advanced features including an A/D Converter. These multi-chip CMOS devices are suited for applications requiring a full featured controller with an 8-bit A/D converter, and as pre-production devices for a masked ROM design. Pin and software compatible 16k or 32k OTP EPROM versions are available (COP87L88GD/RD Family) for pre-production, and for use with a range of COP8 software and hardware development tools. Family features include an 8-bit memory mapped architecture, 10 MHz CKI with 1µs instruction cycle, three multifunction 16-bit timer/counters, MICROWIRE/PLUS™ serial I/O, one 8-bit/8-channel A/D converter with prescaler and both differential and single ended modes, two power saving HALT/IDLE modes, MIWU, idle timer, high current outputs, software selectable I/O options, WATCHDOG™ timer and Clock Monitor, 2.5V to 5.5V operation, program code security, and 44 pin package. Devices included in this datasheet are: Device Memory (bytes) RAM (bytes) I/O Pins Packages Temperature COP688GD 16k ROM 256 40 44 PLCC -55 to +125˚C 4.5V to 5.5V Comments COP888GD 16k ROM 256 40 44 PLCC -40 to +85˚C 2.5V to 5.5V COP988GD 16k ROM 256 40 44 PLCC 0 to +70˚C 2.5V to 4.0V, GDH = 4.0V to 6.0V Key Features CPU/Instruction Set Features n 8-channel A/D converter with prescaler and both differential and single ended modes n Three 16-bit timers, each with two 16-bit registers supporting: — Processor Independent PWM mode — External Event counter mode — Input Capture mode n Quiet design (low radiated emissions) n 16 kbytes on-board ROM n 256 bytes on-board RAM n 1 µs instruction cycle time n Twelve multi-source vectored interrupts servicing — External Interrupt — Idle Timer T0 — Three Timers (each with 2 Interrupts) — MICROWIRE/PLUS — Multi-Input Wake Up — Software Trap — Default VIS (default interrupt) n Versatile and easy to use instruction set n 8-bit Stack Pointer (SP) – stack in RAM n Two 8-bit Register Indirect Data Memory Pointers (B and X) Additional Peripheral Features n n n n Idle Timer Multi-Input Wakeup (MIWU) with optional interrupts (8) WATCHDOG and clock monitor logic MICROWIRE/PLUS serial I/O I/O Features n Memory mapped I/O n Software selectable I/O options (TRI-STATE ® Output, Push-Pull Output, Weak Pull Up Input, High Impedance Input) n Schmitt trigger inputs on ports G and L n Package: — 44 PLCC with 40 I/O pins Fully Static CMOS n Two power saving modes: HALT and IDLE n Single supply operation: 2.5V to 5.5V n Temperature range: −0˚C to +70˚C and −40˚C to +85˚C Development Support n Emulation and OTP devices n Real time emulation and full program debug offered by MetaLink Development System TRI-STATE ® is a registered trademark of National Semiconductor Corporation. MICROWIRE/PLUS™, COP8™, MICROWIRE™ and WATCHDOG™ are trademarks of National Semiconductor Corporation. iceMASTER ® is a registered trademark of MetaLink Corporation. © 1999 National Semiconductor Corporation DS100076 www.national.com COP888GD 8-Bit CMOS ROM Based Microcontrollers with 16k Memory and 8-Channel A/D July 1999 Block Diagram DS100076-1 FIGURE 1. Block Diagram Connection Diagrams Plastic Chip Carrier DS100076-2 Top View Order Number COP888GD-XXXV, COP988GD-XXX/V See NS Plastic Chip Package Number V44A FIGURE 2. Connection Diagrams www.national.com 2 Connection Diagrams (Continued) Pinouts for 44-Pin Package Port Type Alt. Fun Alt. Fun 44-Pin Pack. L0 I/O MIWU 17 L1 I/O MIWU 18 L2 I/O MIWU 19 L3 I/O MIWU L4 I/O MIWU T2A 25 L5 I/O MIWU T2B 26 L6 I/O MIWU T3A 27 L7 I/O MIWU T3B G0 I/O INT G1 WDOUT G2 I/O T1B 41 G3 I/O T1A 42 G4 I/O SO 3 G5 I/O SK 4 G6 I SI 5 G7 I/CKO HALT Restart D0 O 29 D1 O 30 D2 O 31 D3 O 32 D4 O 33 D5 O 34 D6 O 35 D7 O I0 I ACH0 9 I1 I ACH1 10 I2 I ACH2 11 I3 I ACH3 12 I4 I ACH4 13 I5 I ACH5 14 I6 I ACH6 15 I7 I ACH7 16 C0 I/O 43 C1 I/O 44 C2 I/O 1 C3 I/O 2 C4 I/O 21 C5 I/O 22 C6 I/O 23 C7 I/O 24 20 28 39 40 6 36 VCC 8 GND 37 CKI 7 RESET 38 3 www.national.com Absolute Maximum Ratings (Note 1) (Source) Total Current out of GND Pin (Sink) Storage Temperature Range If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VCC) Voltage at Any Pin Total Current into VCC Pin 100 mA 110 mA −65˚C to +140˚C Note 1: Absolute maximum ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications are not ensured when operating the device at absolute maximum ratings. 7V −0.3V to VCC + 0.3V DC Electrical Characteristics −0˚C ≤ TA ≤ +70˚C unless otherwise specified Parameter Conditions Operating Voltage Power Supply Ripple (Note 3) Min 2.5 Peak-to-Peak Typ Max Units 5.5 V 0.1 VCC V Supply Current (Note 4) CKI = 10 MHz VCC = 5.5V, tc = 1 µs 20 mA CKI = 4 MHz VCC = 4.0V, tc = 2.5 µs 10 mA VCC = 5.5V, CKI = 0 MHz 12 µA VCC = 4.0V, CKI = 0 MHz 10 µA CKI = 10 MHz VCC = 5.5V, tc = 1 µs 1.2 mA CKI = 4 MHz VCC = 4.0V, tc = 2.5 µs 1 mA HALT Current (Note 5) IDLE Current (Note 4) Input Levels RESET , CKI Logic High 0.8 VCC Logic Low V 0.2 VCC V All Other Inputs (L0-L7, G0-G6, C0-C7, I0-I7) Logic High 0.7 VCC V 0.2 VCC V Hi-Z Input Leakage VCC = 5.5V −2 +2 µA Input Pullup Current VCC = 5.5V, VIN = 0V −40 −250 µA 0.35 VCC V Logic Low G and L Port Input Hysteresis (Note 9) Output Current Levels D Outputs Source VCC = 4.5V, VOH = 3.3V Sink (Note 6) −0.4 mA VCC = 4.5V, VOL = 1V 10 mA Source (Weak Pull-Up Mode) VCC = 4.5V, VOH = 2.7V −10 Source (Push-Pull Mode) VCC = 4.5V, VOH = 3.3V −0.4 mA Sink (Push-Pull Mode) VCC = 4.5V, VOL = 0.4V 1.6 mA VCC = 5.5V −2 All Others TRI-STATE Leakage −100 µA +2 µA 15 mA Allowable Sink/Source Current per Pin D Outputs (Sink) www.national.com 4 DC Electrical Characteristics (Continued) −0˚C ≤ TA ≤ +70˚C unless otherwise specified Parameter Conditions Min Typ All others Maximum Input Current Room Temp Max Units 3 mA ± 100 mA without Latchup (Note 7) (Note 9) RAM Retention Voltage, Vr 500 ns Rise 2 V and Fall Time (min) Input Capacitance Load Capacitance on D2 7 pF 1000 pF Note 2: tc = Instruction Cycle Time Note 3: Maximum rate of voltage change must be < 0.5 V/ms. Note 4: Supply and IDLE currents are measured with CKI driven with a square wave Oscillator, CKO driven 180˚ out of phase with CKI, inputs connected to VCC and outputs driven low but not connected to a load. Note 5: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations by bringing CKI high. Measurement of IDD HALT is done with device neither sourcing nor sinking current; with L, C, G0, and G2–G5 programmed as low outputs and not driving a load; all outputs programmed low and not driving a load; all inputs tied to VCC; clock monitor and comparator disabled. Parameter refers to HALT mode entered via setting bit 7 of the G Port data register. Part will pull up CKI during HALT in crystal clock mode. Note 6: The user must guarantee that D2 pin does not source more than 10 mA during RESET. If D2 sources more than 10 mA during reset, the device will go into programming mode. Note 7: Pins G6 and RESET are designed with a high voltage input network. These pins allow input voltages VCC and the pins will have sink current to VCC when biased at voltages VCC (the pins do not have source current when biased at a voltage below VCC). The effective resistance to VCC is 750Ω (typical). These two pins will not latch up. The voltage at the pins must be limited to < 14V. WARNING: Voltages in excess of 14V will cause damage to the pins. This warning excludes ESD transients. Note 8: The output propagation delay is referenced to the end of the instruction cycle where the output change occurs. Note 9: Parameter characterized but not tested. AC Electrical Characteristics −40˚C ≤ TA ≤ +85˚C unless otherwise specified Parameter Conditions Min Typ Max Units Instruction Cycle Time (tc) Crystal, Resonator, 4.5V ≤ VCC ≤ 5.5V 1.0 DC µs R/C Oscillator 4.5V ≤ VCC ≤ 5.5V 3.0 DC µs fr = Max 40 60 CKI Clock Duty Cycle (Note 9) Rise Time (Note 9) fr = 10 MHz Ext Clock 5 ns Fall Time (Note 9) fr = 10 MHz Ext Clock 5 ns Inputs tSETUP 4.5V ≤ VCC ≤ 5.5V 200 ns tHOLD 4.5V ≤ VCC ≤ 5.5V 60 ns Output Propagation Delay (Note 8) RL = 2.2k, CL = 100 pF tPD1, tPD0 SO, SK 4.5V ≤ VCC ≤ 5.5V 0.7 µs All Others 4.5V ≤ VCC ≤ 5.5V 1.0 µs MICROWIRE™ Setup Time (tUWS) (Note 9) 20 MICROWIRE Hold Time (tUWH) (Note 9) 56 ns ns 220 MICROWIRE Output Propagation Delay (tUPD) ns Input Pulse Width (Note 9) Interrupt Input High Time 1.0 tc Interrupt Input Low Time 1.0 tc Timer 1, 2, 3 Input High Time 1.0 tc Timer 1, 2, 3 Input Low Time 1.0 tc 1.0 µs Reset Pulse Width Note 10: tc = Instruction Cycle Time Note 11: Maximum rate of voltage change must be < 0.5 V/ms. 5 www.national.com AC Electrical Characteristics (Continued) Note 12: Supply and IDLE currents are measured with CKI driven with a square wave Oscillator, CKO driven 180˚ out of phase with CKI, inputs connected to VCC and outputs driven low but not connected to a load. Note 13: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations by bringing CKI high. Measurement of IDD HALT is done with device neither sourcing nor sinking current; with L, C, G0, and G2–G5 programmed as low outputs and not driving a load; all outputs programmed low and not driving a load; all inputs tied to VCC; clock monitor and comparator disabled. Parameter refers to HALT mode entered via setting bit 7 of the G Port data register. Part will pull up CKI during HALT in crystal clock mode. Note 14: The user must guarantee that D2 pin does not source more than 10 mA during RESET. If D2 sources more than 10 mA during reset, the device will go into programming mode. Note 15: Pins G6 and RESET are designed with a high voltage input network. These pins allow input voltages VCC and the pins will have sink current to VCC when biased at voltages VCC (the pins do not have source current when biased at a voltage below VCC). The effective resistance to VCC is 750Ω (typical). These two pins will not latch up. The voltage at the pins must be limited to < 14V. WARNING: Voltages in excess of 14V will cause damage to the pins. This warning excludes ESD transients. Note 16: The output propagation delay is referenced to the end of the instruction cycle where the output change occurs. Note 17: Parameter characterized but not tested. www.national.com 6 Absolute Maximum Ratings (Note 1) (Source) Total Current out of GND Pin (Sink) Storage Temperature Range If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VCC) Voltage at Any Pin Total Current into VCC Pin 100 mA 110 mA −65˚C to +140˚C Note 18: Absolute maximum ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications are not ensured when operating the device at absolute maximum ratings. 7V −0.3V to VCC + 0.3V DC Electrical Characteristics −40˚C ≤ TA ≤ +85˚C unless otherwise specified Parameter Conditions Operating Voltage Power Supply Ripple (Note 3) Min 2.7 Peak-to-Peak Typ Max Units 5.5 V 0.1 VCC V Supply Current (Note 4) CKI = 10 MHz VCC = 5.5V, tc = 1 µs 20 mA CKI = 4 MHz VCC = 4.0V, tc = 2.5 µs 10 mA VCC = 5.5V, CKI = 0 MHz 12 µA VCC = 4.0V, CKI = 0 MHz 10 µA CKI = 10 MHz VCC = 5.5V, tc = 1 µs 1.2 mA CKI = 4 MHz VCC = 4.0V, tc = 2.5 µs 1 mA HALT Current (Note 5) IDLE Current (Note 4) Input Levels RESET , CKI Logic High 0.8 VCC Logic Low V 0.2 VCC V All Other Inputs (L0-L7, G0-G6, C0-C7, I0-I7) Logic High 0.7 VCC V 0.2 VCC V Hi-Z Input Leakage VCC = 5.5V −2 +2 µA Input Pullup Current VCC = 5.5V, VIN = 0V −40 −250 µA 0.35 VCC V Logic Low G and L Port Input Hysteresis (Note 9) Output Current Levels D Outputs Source VCC = 4.5V, VOH = 3.3V Sink (Note 6) −0.4 mA VCC = 4.5V, VOL = 1V 10 mA Source (Weak Pull-Up Mode) VCC = 4.5V, VOH = 2.7V −10 Source (Push-Pull Mode) VCC = 4.5V, VOH = 3.3V −0.4 mA Sink (Push-Pull Mode) VCC = 4.5V, VOL = 0.4V 1.6 mA VCC = 5.5V −2 All Others TRI-STATE Leakage −100 µA +2 µA 15 mA Allowable Sink/Source Current per Pin D Outputs (Sink) 7 www.national.com DC Electrical Characteristics (Continued) −40˚C ≤ TA ≤ +85˚C unless otherwise specified Parameter Conditions Min Typ All others Maximum Input Current Room Temp Max Units 3 mA ± 100 mA without Latchup (Note 7) (Note 9) RAM Retention Voltage, Vr 500 ns Rise 2 V and Fall Time (min) Input Capacitance Load Capacitance on D2 7 pF 1000 pF AC Electrical Characteristics −40˚C ≤ TA ≤ +85˚C unless otherwise specified Parameter Conditions Min Typ Max Units Instruction Cycle Time (tc) Crystal, Resonator, 4.5V ≤ VCC ≤ 5.5V 1.0 DC µs R/C Oscillator 4.5V ≤ VCC ≤ 5.5V 3.0 DC µs fr = Max 40 60 CKI Clock Duty Cycle (Note 9) Rise Time (Note 9) fr = 10 MHz Ext Clock 5 ns Fall Time (Note 9) fr = 10 MHz Ext Clock 5 ns Inputs tSETUP 4.5V ≤ VCC ≤ 5.5V 200 ns tHOLD 4.5V ≤ VCC ≤ 5.5V 60 ns Output Propagation Delay (Note 8) RL = 2.2k, CL = 100 pF tPD1, tPD0 SO, SK 4.5V ≤ VCC ≤ 5.5V 0.7 µs All Others 4.5V ≤ VCC ≤ 5.5V 1.0 µs MICROWIRE Setup Time (tUWS) (Note 9) 20 MICROWIRE Hold Time (tUWH) (Note 9) 56 ns ns 220 MICROWIRE Output Propagation Delay (tUPD) ns Input Pulse Width (Note 9) Interrupt Input High Time 1.0 tc Interrupt Input Low Time 1.0 tc Timer 1, 2, 3 Input High Time 1.0 tc Timer 1, 2, 3 Input Low Time 1.0 tc 1.0 µs Reset Pulse Width Note 19: tc = Instruction Cycle Time Note 20: Maximum rate of voltage change must be < 0.5 V/ms. Note 21: Supply and IDLE currents are measured with CKI driven with a square wave Oscillator, CKO driven 180˚ out of phase with CKI, inputs connected to VCC and outputs driven low but not connected to a load. Note 22: The HALT mode will stop CKI from oscillating in the RC and the Crystal configurations by bringing CKI high. Measurement of IDD HALT is done with device neither sourcing nor sinking current; with L, C, G0, and G2–G5 programmed as low outputs and not driving a load; all outputs programmed low and not driving a load; all inputs tied to VCC; clock monitor and comparator disabled. Parameter refers to HALT mode entered via setting bit 7 of the G Port data register. Part will pull up CKI during HALT in crystal clock mode. Note 23: The user must guarantee that D2 pin does not source more than 10 mA during RESET. If D2 sources more than 10 mA during reset, the device will go into programming mode. Note 24: Pins G6 and RESET are designed with a high voltage input network. These pins allow input voltages VCC and the pins will have sink current to VCC when biased at voltages VCC (the pins do not have source current when biased at a voltage below VCC). The effective resistance to VCC is 750Ω (typical). These two pins will not latch up. The voltage at the pins must be limited to < 14V. WARNING: Voltages in excess of 14V will cause damage to the pins. This warning excludes ESD transients. Note 25: The output propagation delay is referenced to the end of the instruction cycle where the output change occurs. Note 26: Parameter characterized but not tested. www.national.com 8 A/D Converter Specifications VCC = 5V ± 10%, (VSS–0.050V) ≤ Any Input ≤ (VCC + 0.050V) Parameter Conditions Min Typ Resolution Absolute Accuracy Non-Linearity Deviation from the Best Straight Line Differential Non-Linearity Common Mode Input Range GND DC Common Mode Error Max Units 8 Bits ±2 ±1 LSB ±1 LSB LSB VCC V ± 1/2 LSB µA Off Channel Leakage Current 1 2 On Channel Leakage Current 1 2 µA 1.67 MHz A/D Clock Frequency 0.1 Converison Time 17 Internal Reference Resistance A/D Clock Cycles 1 µs Tum-on Time Note 27: Conversion Time includes 7 A/D clock cycles sample and hold time. Note 28: See Prescaler description. Note 29: For VIN(−) = VIN (+) the digital output code will be 0000 0000. Two on-chip diodes are tied to each analog input. The diodes will forward conduct for analog input voltages below ground or above the VCC supply. Be careful, during testing at low VCC levels (4.5V), as high level analog inputs (5V) can cause this input diode to conduct — especially at elevated temperatures, and cause errors for analog inputs near full-scale. The spec allows 50 mV forward bias of either diode. This means that as long as the analog VIN does not exceed the supply voltage by more than 50 mV, the output code will be correct. To achieve an absolute 0 VDC to 5 VDC input voltage range will therefore require a minimum supply voltage of 4.950 VDC over temperature variations, initial tolerance and loading. Note 30: Time or internal reference reistance to turn on and settle after coming out of HALT or IDLE mode. DS100076-4 FIGURE 3. MICROWIRE/PLUS Timing 9 www.national.com Typical Performance Characteristics (−55˚C ≤ TA = +125˚C) DS100076-19 DS100076-20 DS100076-21 DS100076-22 DS100076-23 www.national.com 10 configuration registers for G6 and G7 are used for special purpose functions as outlined on the next page. Reading the G6 and G7 data bits will return zeros. Pin Descriptions VCC and GND are the power supply pins. All VCC and GND pins must be connected. CKI is the clock input. This can come from an R/C generated oscillator, or a crystal oscillator (in conjunction with CKO). See Oscillator Description section. RESET is the master reset input. See Reset Description section. The device contains three bidirectional 8-bit I/O ports (C, G and L), where each individual bit may be independently configured as an input (Schmitt Trigger inputs on ports L and G), output or TRI-STATE under program control. Three data memory address locations are allocated for each of these I/O ports. Each I/O port has two associated 8-bit memory mapped registers, the CONFIGURATION register and the output DATA register. A memory mapped address is also reserved for the input pins of each I/O port. (See the memory map for the various addresses associated with the I/O ports.) Figure 4 shows the I/O port configurations. The DATA and CONFIGURATION registers allow for each port bit to be individually configured under software control as shown below: CONFIGURATION DATA Register Register 0 0 0 1 Input with Weak Pull-Up 1 0 Push-Pull Zero Output 1 1 Push-Pull One Output DS100076-5 FIGURE 4. I/O Port Configurations Note that the chip will be placed in the HALT mode by writing a “1” to bit 7 of the Port G Data Register. Similarly the chip will be placed in the IDLE mode by writing a “1” to bit 6 of the Port G Data Register. Writing a “1” to bit 6 of the Port G Configuration Register enables the MICROWIRE/PLUS to operate with the alternate phase of the SK clock. The G7 configuration bit, if set high, enables the clock start up delay after HALT when the R/C clock configuration is used. Port Set-Up Hi-Z Input (TRI-STATE Output) Config Reg. PORT L is an 8-bit I/O port. All L-pins have Schmitt triggers on the inputs. Port L supports Multi-Input Wake Up on all eight pins. L4 and L5 are used for the timer input functions T2A and T2B. L6 and L7 are used for the timer input functions T3A and T3B. Port L has the following alternate features: L7 MIWU or T3B L6 MIWU or T3A L5 MIWU or T2B L4 MIWU or T2A L3 MIWU L2 MIWU L1 MIWU L0 MIWU Port G is an 8-bit port with 5 I/O pins (G0, G2–G5), an input pin (G6), and a dedicated output pin (G7). Pins G0 and G2–G6 all have Schmitt Triggers on their inputs. Pin G1 serves as the dedicated WDOUT WATCHDOG output, while pin G7 is either input or output depending on the oscillator mask option selected. With the crystal oscillator option selected, G7 serves as the dedicated output pin for the CKO clock output. With the single-pin R/C oscillator mask option selected, G7 serves as a general purpose input pin but is also used to bring the device out of HALT mode with a low to high transition on G7. There are two registers associated with the G Port, a data register and a configuration register. Therefore, each of the 5 I/O bits (G0, G2–G5) can be individually configured under software control. Data Reg. G7 CLKDLY HALT G6 Alternate SK IDLE Port G has the following alternate features: G6 SI (MICROWIRE Serial Data Input) G5 SK (MICROWIRE Serial Clock) G4 SO (MICROWIRE Serial Data Output) G3 T1A (Timer T1 I/O) G2 T1B (Timer T1 Capture Input) G0 INTR (External Interrupt Input) Port G has the following dedicated functions: G7 CKO Oscillator dedicated output or general purpose input G1 WDOUT WATCHDOG and/or Clock Monitor dedicated output Port C is an 8-bit I/O port. The 40-pin device does not have a full complement of Port C pins. The unavailable pins are not terminated. A read operation for these unterminated pins will return unpredicatable values. Port I is an 8-bit Hi-Z input port, and also provides the analog inputs to the A/D converter. The 28-pin device does not have a full complement of Port I pins. The unavailable pins are not terminated (i.e. they are floating). A read operation from these unterminated pins will return unpredictable values. The user should ensure that the software takes this into account by either masking out these inputs, or else restricting the accesses to bit operations only. If unterminated, Port I pins will draw power only when addressed. Since G6 is an input only pin and G7 is the dedicated CKO clock output pin (crystal clock option) or general purpose input (R/C clock option), the associated bits in the data and 11 www.national.com Pin Descriptions registers X, SP, B and S are memory mapped into this space at address locations 0FC to 0FF Hex respectively, with the other registers being available for general usage. The instruction set permits any bit in memory to be set, reset or tested. All I/O and registers (except A and PC) are memory mapped; therefore, I/O bits and register bits can be directly and individually set, reset and tested. The accumulator (A) bits can also be directly and individually tested. (Continued) Port D is an 8-bit output port that is preset high when RESET goes low. The user can tie two or more D port outputs (except D2) together in order to get a higher drive. Note: Care must be exercised with the D2 pin operation. At RESET, the external loads on this pin must ensure that the output voltages stay above 0.8 VCC to prevent the chip from entering special modes. Also keep the external loading on D2 to < 1000 pF. Note: RAM contents are undefined upon power-up. Functional Description Data Memory Segment RAM Extension The architecture of the device is modified Harvard architecture. With the Harvard architecture, the control store program memory (ROM) is separated from the data store memory (RAM). Both ROM and RAM have their own separate addressing space with separate address buses. The architecture, though based on Harvard architecture, permits transfer of data from ROM to RAM. Data memory address 0FF is used as a memory mapped location for the Data Segment Address Register (S). The data store memory is either addressed directly by a single byte address within the instruction, or indirectly relative to the reference of the B, X, or SP pointers (each contains a single-byte address). This single-byte address allows an addressing range of 256 locations from 00 to FF hex. The upper bit of this single-byte address divides the data store memory into two separate sections as outlined previously. With the exception of the RAM register memory from address locations 00F0 to 00FF, all RAM memory is memory mapped with the upper bit of the single-byte address being equal to zero. This allows the upper bit of the single-byte address to determine whether or not the base address range (from 0000 to 00FF) is extended. If this upper bit equals one (representing address range 0080 to 00FF), then address extension does not take place. Alternatively, if this upper bit equals zero, then the data segment extension register S is used to extend the base address range (from 0000 to 007F) from XX00 to XX7F, where XX represents the 8 bits from the S register. Thus the 128-byte data segment extensions are located from addresses 0100 to 017F for data segment 1, 0200 to 027F for data segment 2, etc., up to FF00 to FF7F for data segment 255. The base address range from 0000 to 007F represents data segment 0. CPU REGISTERS The CPU can do an 8-bit addition, subtraction, logical or shift operation in one instruction (tc) cycle time. There are six CPU registers: A is the 8-bit Accumulator Register PC is the 15-bit Program Counter Register PU is the upper 7 bits of the program counter (PC) PL is the lower 8 bits of the program counter (PC) B is an 8-bit RAM address pointer, which can be optionally post auto incremented or decremented. X is an 8-bit alternate RAM address pointer, which can be optionally post auto incremented or decremented. SP is the 8-bit stack pointer, which points to the subroutine/ interrupt stack (in RAM). The SP is initialized to RAM address 06F with reset. S is the 8-bit Data Segment Address Register used to extend the lower half of the address range (00 to 7F) into 256 data segments of 128 bytes each. All the CPU registers are memory mapped with the exception of the Accumulator (A) and the Program Counter (PC). Figure 5 illustrates how the S register data memory extension is used in extending the lower half of the base address range (00 to 7F hex) into 256 data segments of 128 bytes each, with a total addressing range of 32 kbytes from XX00 to XX7F. This organization allows a total of 256 data segments of 128 bytes each with an additional upper base segment of 128 bytes. Furthermore, all addressing modes are available for all data segments. The S register must be changed under program control to move from one data segment (128 bytes) to another. However, the upper base segment (containing the 16 memory registers, I/O registers, control registers, etc.) is always available regardless of the contents of the S register, since the upper base segment (address range 0080 to 00FF) is independent of data segment extension. The instructions that utilize the stack pointer (SP) always reference the stack as part of the base segment (Segment 0), regardless of the contents of the S register. The S register is not changed by these instructions. Consequently, the stack (used with subroutine linkage and interrupts) is always located in the base segment. The stack pointer will be initialized to point at data memory location 006F as a result of reset. PROGRAM MEMORY The program memory consists of 16 kbytes of ROM. These bytes may hold program instructions or constant data (data tables for the LAID instruction, jump vectors for the JID instruction, and interrupt vectors for the VIS instruction). The program memory is addressed by the 15-bit program counter (PC). All interrupts in the devices vector to program memory location 0FF Hex. DATA MEMORY The data memory address space includes the on-chip RAM and data registers, the I/O registers (Configuration, Data and Pin), the control registers, the MICROWIRE/PLUS SIO shift register, and the various registers, and counters associated with the timers (with the exception of the IDLE timer). Data memory is addressed directly by the instruction or indirectly by the B, X, SP pointers and S register. The data memory consists of 256 bytes of RAM. Sixteen bytes of RAM are mapped as “registers” at addresses 0F0 to 0FF Hex. These registers can be loaded immediately, and also decremented and tested with the DRSZ (decrement register and skip if zero) instruction. The memory pointer www.national.com 12 Data Memory Segment RAM Extension (Continued) output will continue until 16 tC–32 tC clock cycles following the clock frequency reaching the minimum specified value, at which time the G1 output will enter the TRI-STATE mode. The external RC network shown in Figure 6 should be used to ensure that the RESET pin is held low until the power supply to the chip stabilizes. DS100076-7 RC > 5 x Power Supply Rise Time FIGURE 6. Recommended Reset Circuit Oscillator Circuits The chip can be driven by a clock input on the CKI input pin which can be between DC and 10 MHz. The CKO output clock is on pin G7 (crystal configuration). The CKI input frequency is divided down by 10 to produce the instruction cycle clock (1/tc). DS100076-6 *Reads as all ones. FIGURE 5. RAM Organization Note: External clocks with frequencies above about 4 MHz require the user to drive the CKO (G7) pin with a signal 180 degrees out of phase with CKI. The 128 bytes of RAM contained in the base segment are split between the lower and upper base segments. The first 112 bytes of RAM are resident from address 0000 to 006F in the lower base segment, while the remaining 16 bytes of RAM represent the 16 data memory registers located at addresses 00F0 to 00FF of the upper base segment. No RAM is located at the upper sixteen addresses (0070 to 007F) of the lower base segment. Additional RAM beyond these initial 128 bytes, however, will always be memory mapped in groups of 128 bytes (or less) at the data segment address extensions (XX00 to XX7F) of the lower base segment. The additional 128 bytes of RAM are memory mapped at address locations 0100 to 017F hex. Figure 7 shows the Crystal and R/C oscillator diagrams. CRYSTAL OSCILLATOR CKI and CKO can be connected to make a closed loop crystal (or resonator) controlled oscillator. Table 1 shows the component values required for various standard crystal values. R/C OSCILLATOR By selecting CKI as a single pin oscillator input, a single pin R/C oscillator circuit can be connected to it. CKO is available as a general purpose input, and/or HALT restart input. Reset Note: Use of the R/C oscillator option will result in higher electromagnetic emissions. The RESET input when pulled low initializes the microcontroller. Initialization will occur whenever the RESET input is pulled low. Upon initialization, the data and configuration registers for ports L, G and C are cleared, resulting in these Ports being initialized to the TRI-STATE mode. Pin G1 of the G Port is an exception (as noted below) since pin G1 is dedicated as the WATCHDOG and/or Clock Monitor error output pin. Port D is set high. The PC, PSW, ICNTRL, CNTRL, T2CNTRL and T3CNTRL control registers are cleared. The Comparator Select Register is cleared. The S register is initialized to zero. The Multi-Input Wakeup registers WKEN and WKEDG are cleared. Wakeup register WKPND is unknown. The stack pointer, SP, is initialized to 6F hex. The device comes out of reset with both the WATCHDOG logic and the Clock Monitor detector armed, with the WATCHDOG service window bits set and the Clock Monitor bit set. The WATCHDOG and Clock Monitor circuits are inhibited during reset. The WATCHDOG service window bits being initialized high default to the maximum WATCHDOG service window of 64k tC clock cycles. The Clock Monitor bit being initialized high will cause a Clock Monitor error following reset if the clock has not reached the minimum specified frequency at the termination of reset. A Clock Monitor error will cause an active low error output on pin G1. This error Table 1 shows the variation in the oscillator frequencies as functions of the component (R and C) values. 13 www.national.com Oscillator Circuits SL1 & SL0 (Continued) Select the MICROWIRE/PLUS clock divide by (00 = 2, 01 = 4, 1x = 8) PSW Register (Address X'00EF) HC C T1PNDA T1ENA EXPND BUSY EXEN Bit 7 GIE Bit 0 The PSW register contains the following select bits: HC Half Carry Flag C Carry Flag T1PNDA Timer T1 Interrupt Pending Flag (Autoreload RA in mode 1, T1 Underflow in Mode 2, T1A capture edge in mode 3) T1ENA DS100076-8 EXPND BUSY EXEN Enable external interrupt GIE Global interrupt enable (enables interrupts) The Half-Carry flag is also affected by all the instructions that affect the Carry flag. The SC (Set Carry) and R/C (Reset Carry) instructions will respectively set or clear both the carry flags. In addition to the SC and R/C instructions, ADC, SUBC, RRC and RLC instructions affect the Carry and Half Carry flags. DS100076-9 FIGURE 7. Crystal and R/C Oscillator Diagrams TABLE 1. Crystal Oscillator Configuration, TA = 25˚C R1 R2 C1 C2 CKI Freq (kΩ) (MΩ) (pF) (pF) (MHz) 0 1 30 30–36 10 0 1 30 30–36 4 0 1 200 100–150 0.455 ICNTRL Register (Address X'00E8) Conditions Reserved C CKI Freq Instr. Cycle (kΩ) (pF) (MHz) (µs) 3.3 82 2.2 to 2.7 3.7 to 4.6 5.6 100 1.1 to 1.3 7.4 to 9.0 6.8 100 0.9 to 1.1 8.8 to 10.8 Conditions VCC = 5V VCC = 5V VCC = 5V 50 pF ≤ C ≤ 200 pF T2C3 T1C1 T1C0 MSEL IEDG MSEL IEDG www.national.com µWEN T1PNDB T1ENB T2C2 SL1 T2C1 T2C0 T2PNDA T2ENA T2PNDB T2ENB Bit 0 The T2CNTRL control register contains the following bits: T2C3 Timer T2 mode control bit SL0 Bit 0 T2C2 T2C1 T2C0 The Timer1 (T1) and MICROWIRE/PLUS control register contains the following bits: T1C3 Timer T1 mode control bit T1C2 Timer T1 mode control bit T1C1 Timer T1 mode control bit T1C0 µWPND Bit 0 Bit 7 CNTRL Register (Address X'00EE) T1C2 T0EN T2CNTRL Register (Address X'00C6) CONTROL REGISTERS T1C3 T0PND The ICNTRL register contains the following bits: Reserved This bit is reserved and should to zero LPEN L Port Interrupt Enable (Multi-Input Wakeup/ Interrupt) T0PND Timer T0 Interrupt pending T0EN Timer T0 Interrupt Enable (Bit 12 toggle) µWPND MICROWIRE/PLUS interrupt pending µWEN Enable MICROWIRE/PLUS interrupt T1PNDB Timer T1 Interrupt Pending Flag for T1B capture edge T1ENB Timer T1 Interrupt Enable for T1B Input capture edge Note 31: 3k ≤ R ≤ 200k Bit 7 LPEN Bit 7 VCC = 5V VCC = 5V VCC = 5V TABLE 2. RC Oscillator Configuration, TA = 25˚C R Timer T1 Interrupt Enable for Timer Underflow or T1A Input capture edge External interrupt pending MICROWIRE/PLUS busy shifting flag T2PNDA Timer T1 Start/Stop control in timer modes 1 and 2, T1 Underflow Interrupt Pending Flag in timer mode 3 Selects G5 and G4 as MICROWIRE/PLUS signals SK and SO respectively External interrupt edge polarity select (0 = Rising edge, 1 = Falling edge) T2ENA T2PNDB 14 Timer T2 mode control bit Timer T2 mode control bit Timer T2 Start/Stop control in timer modes 1 and 2, T2 Underflow Interrupt Pending Flag in timer mode 3 Timer T2 Interrupt Pending Flag (Autoreload RA in mode 1, T2 Underflow in mode 2, T2A capture edge in mode 3) Timer T2 Interrupt Enable for Timer Underflow or T2A Input capture edge Timer T2 Interrupt Pending Flag for T2B capture edge CONTROL REGISTERS T2ENB Bits 11 through 15 of the ITMR register can be selected for triggering the IDLE Timer interrupt. Each time the selected bit underflows (every 4k, 8k, 16k, 32k or 64k instruction cycles), the IDLE Timer interrupt pending bit T0PND is set, thus generating an interrupt (if enabled), and bit 6 of the Port G data register is reset, thus causing an exit from the IDLE mode if the device is in that mode. In order for an interrupt to be generated, the IDLE Timer interrupt enable bit T0EN must be set, and the GIE (Global Interrupt Enable) bit must also be set. The T0PND flag and T0EN bit are bits 5 and 4 of the ICNTRL register, respectively. The interrupt can be used for any purpose. Typically, it is used to perform a task upon exit from the IDLE mode. For more information on the IDLE mode, refer to the Power Save Modes section. The Idle Timer period is selected by bits 0–2 of the ITMR register Bits 3–7 of the ITMR Register are reserved and should not be used as software flags. (Continued) Timer T2 Interrupt Enable for Timer Underflow or T2B Input capture edge T3CNTRL Register (Address X'00B6) T3C3 T3C2 T3C1 T3C0 T3PNDA T3ENA T3PNDB T3ENB Bit 7 Bit 0 The T3CNTRL control register contains the following bits: T3C3 Timer T3 mode control bit T3C2 T3C1 T3C0 T3PNDA T3ENA T3PNDB T3ENB Timer T3 mode control bit Timer T3 mode control bit Timer T3 Start/Stop control in timer modes 1 and 2, T3 Underflow Interrupt Pending Flag in timer mode 3 Timer T3 Interrupt Pending Flag (Autoreload RA in mode 1, T3 Underflow in mode 2, T3A capture edge in mode 3) Timer T3 Interrupt Enable for Timer Underflow or T3A Input capture edge Timer T3 Interrupt Pending Flag for T3B capture edge Timer T3 Interrupt Enable for Timer Underflow or T3B Input capture edge TABLE 3. Idle Timer Window Length ITSEL2 ITSEL1 ITSEL0 Idle Timer Period (Instruction Cycles) 0 0 0 0 0 1 4,096 8,192 0 1 0 16,384 Timers 0 1 1 32,768 The device contains a very versatile set of timers (T0, T1, T2, T3). All timers and associated autoreload/capture registers power up containing random data. 1 X X 65,536 The ITMR is cleared on Reset and the Idle Timer period is reset to 4,096 instruction cycles. TIMER T0 (IDLE TIMER) The device supports applications that require maintaining real time and low power with the IDLE mode. This IDLE mode support is furnished by the IDLE timer T0, which is a 16-bit timer. The Timer T0 runs continuously at the fixed rate of the instruction cycle clock, tc. The user cannot read or write to the IDLE Timer T0, which is a count down timer. The Timer T0 supports the following functions: ITMR Register (Address X’0xCF) Reserved Bit 7 ITSEL2 ITSEL1 ITSEL0 Bit 0 Any time the IDLE Timer period is changed there is the possibility of generating a spurious IDLE Timer interrupt by setting the T0PND bit. The user is advised to disable IDLE Timer interrupts prior to changing the value of the ITSEL bits of the ITMR Register and then clear the T0PND bit before attempting to synchronize operation to the IDLE Timer. j Exit out of the Idle Mode (See Idle Mode description) j WATCHDOG logic (See WATCHDOG description) j Start up delay out of the HALT mode Figure 8 is a functional block diagram showing the structure of the IDLE Timer and its associated interrupt logic. 15 www.national.com Timers (Continued) DS100076-17 FIGURE 8. Functional Block Diagram for Idle Timer T0 the register RxA. Subsequent underflows cause the timer to be reloaded from the registers alternately beginning with the register RxB. The Tx Timer control bits, TxC3, TxC2 and TxC1 set up the timer for PWM mode operation. TIMER T1, TIMER T2 AND TIMER T3 The device has a set of three powerful timer/counter blocks, T1, T2 and T3. The associated features and functioning of a timer block are described by referring to the timer block Tx. Since the three timer blocks, T1, T2 and T3 are identical, all comments are equally applicable to any of the three timer blocks. Each timer block consists of a 16-bit timer, Tx, and two supporting 16-bit autoreload/capture registers, RxA and RxB. Each timer block has two pins associated with it, TxA and TxB. The pin TxA supports I/O required by the timer block, while the pin TxB is an input to the timer block. The powerful and flexible timer block allows the device to easily perform all timer functions with minimal software overhead. The timer block has three operating modes: Processor Independent PWM mode, External Event Counter mode, and Input Capture mode. Figure 9 shows a block diagram of the timer in PWM mode. The underflows can be programmed to toggle the TxA output pin. The underflows can also be programmed to generate interrupts. Underflows from the timer are alternately latched into two pending flags, TxPNDA and TxPNDB. The user must reset these pending flags under software control. Two control enable flags, TxENA and TxENB, allow the interrupts from the timer underflow to be enabled or disabled. Setting the timer enable flag TxENA will cause an interrupt when a timer underflow causes the RxA register to be reloaded into the timer. Setting the timer enable flag TxENB will cause an interrupt when a timer underflow causes the RxB register to be reloaded into the timer. Resetting the timer enable flags will disable the associated interrupts. Either or both of the timer underflow interrupts may be enabled. This gives the user the flexibility of interrupting once per PWM period on either the rising or falling edge of the PWM output. Alternatively, the user may choose to interrupt on both edges of the PWM output. The control bits TxC3, TxC2, and TxC1 allow selection of the different modes of operation. Mode 1. Processor Independent PWM Mode As the name suggests, this mode allows the device to generate a PWM signal with very minimal user intervention. The user only has to define the parameters of the PWM signal (ON time and OFF time). Once begun, the timer block will continuously generate the PWM signal completely independent of the microcontroller. The user software services the timer block only when the PWM parameters require updating. In this mode the timer Tx counts down at a fixed rate of tc. Upon every underflow the timer is alternately reloaded with the contents of supporting registers, RxA and RxB. The very first underflow of the timer causes the timer to reload from www.national.com 16 Timers TxC3, TxC2 and TxC1, allow the trigger events to be specified either as a positive or a negative edge. The trigger condition for each input pin can be specified independently. (Continued) The trigger conditions can also be programmed to generate interrupts. The occurrence of the specified trigger condition on the TxA and TxB pins will be respectively latched into the pending flags, TxPNDA and TxPNDB. The control flag TxENA allows the interrupt on TxA to be either enabled or disabled. Setting the TxENA flag enables interrupts to be generated when the selected trigger condition occurs on the TxA pin. Similarly, the flag TxENB controls the interrupts from the TxB pin. Underflows from the timer can also be programmed to generate interrupts. Underflows are latched into the timer TxC0 pending flag (the TxC0 control bit serves as the timer underflow interrupt pending flag in the Input Capture mode). Consequently, the TxC0 control bit should be reset when entering the Input Capture mode. The timer underflow interrupt is enabled with the TxENA control flag. When a TxA interrupt occurs in the Input Capture mode, the user must check both the TxPNDA and TxC0 pending flags in order to determine whether a TxA input capture or a timer underflow (or both) caused the interrupt. DS100076-10 FIGURE 9. Timer in PWM Mode Mode 2. External Event Counter Mode This mode is quite similar to the processor independent PWM mode described above. The main difference is that the timer, Tx, is clocked by the input signal from the TxA pin. The Tx timer control bits, TxC3, TxC2 and TxC1 allow the timer to be clocked either on a positive or negative edge from the TxA pin. Underflows from the timer are latched into the TxPNDA pending flag. Setting the TxENA control flag will cause an interrupt when the timer underflows. In this mode the input pin TxB can be used as an independent positive edge sensitive interrupt input if the TxENB control flag is set. The occurrence of a positive edge on the TxB input pin is latched into the TxPNDB flag. Figure 11 shows a block diagram of the timer in Input Capture mode. Figure 10 shows a block diagram of the timer in External Event Counter mode. Note: The PWM output is not available in this mode since the TxA pin is being used as the counter input clock. DS100076-12 FIGURE 11. Timer in Input Capture Mode TIMER CONTROL FLAGS The control bits and their functions are summarized below. TxC3 Timer mode control TxC2 TxC1 TxC0 DS100076-11 FIGURE 10. Timer in External Event Counter Mode Timer mode control Timer mode control Timer Start/Stop control in Modes 1 and 2 (Processor Independent PWM and External Event Counter), where 1 = Start, 0 = Stop Timer Mode TxPNDA Timer TxENA Timer Mode 3. Input Capture Mode The device can precisely measure external frequencies or time external events by placing the timer block, Tx, in the input capture mode. In this mode, the timer Tx is constantly running at the fixed tc rate. The two registers, RxA and RxB, act as capture registers. Each register acts in conjunction with a pin. The register RxA acts in conjunction with the TxA pin and the register RxB acts in conjunction with the TxB pin. The timer value gets copied over into the register when a trigger event occurs on its corresponding pin. Control bits, Underflow Interrupt Pending Flag in 3 (Input Capture) Interrupt Pending Flag Interrupt Enable Flag 1 = Timer Interrupt Enabled 0 = Timer Interrupt Disabled TxPNDB Timer Interrupt Pending Flag TxENB Timer Interrupt Enable Flag 1 = Timer Interrupt Enabled 0 = Timer Interrupt Disabled 17 www.national.com Timers (Continued) The timer mode control bits (TxC3, TxC2 and TxC1) are detailed below: 1 0 1 PWM: TxA Toggle Autoreload RA Autoreload RB 1 0 0 PWM: No TxA Toggle Autoreload RA Autoreload RB 0 0 0 External Event Counter Timer Underflow Pos. TxB Edge Pos. TxA Edge 0 0 1 External Event Counter Timer Underflow Pos. TxB Edge Pos. TxA Edge 0 1 0 Captures: Pos. TxA Edge Pos. TxB Edge tC TxA Pos. Edge or Timer tC 3 0 1 1 1 1 0 1 1 Description Timer Counts On 1 1 TxC1 Interrupt B Source TxC3 2 TxC2 Interrupt A Source Mode TxB Pos. Edge Underflow Captures: Pos. TxA Neg. TxB TxA Pos. Edge Edge or Timer Edge TxB Neg. Edge Underflow Captures: Neg. TxA Neg. TxB TxA Neg. Edge Edge or Timer Edge TxB Neg. Edge Underflow Captures: Neg. TxA Neg. TxB TxA Neg. Edge Edge or Timer Edge TxB Neg. Edge Underflow tC tC tC resonators have a delayed start up time to reach full amplitude and frequency stability. The IDLE timer is used to generate a fixed delay to ensure that the oscillator has indeed stabilized before allowing instruction execution. In this case, upon detecting a valid Wakeup signal, only the oscillator circuitry is enabled. The IDLE timer is loaded with a value of 256 and is clocked with the tc instruction cycle clock. The tc clock is derived by dividing the oscillator clock down by a factor of 10. The Schmitt trigger following the CKI inverter on the chip ensures that the IDLE timer is clocked only when the oscillator has a sufficiently large amplitude to meet the Schmitt trigger specifications. This Schmitt trigger is not part of the oscillator closed loop. The startup timeout from the IDLE timer enables the clock signals to be routed to the rest of the chip. If an RC clock option is being used, the fixed delay is introduced optionally. A control bit, CLKDLY, mapped as configuration bit G7, controls whether the delay is to be introduced or not. The delay is included if CLKDLY is set, and excluded if CLKDLY is reset. The CLKDLY bit is cleared on reset. The device has two mask options associated with the HALT mode. The first mask option enables the HALT mode feature, while the second mask option disables the HALT mode. With the HALT mode enable mask option, the device will enter and exit the HALT mode as described above. With the HALT disable mask option, the device cannot be placed in the HALT mode (writing a “1” to the HALT flag will have no effect, the HALT flag will remain “0”). The WATCHDOG detector circuit is inhibited during the HALT mode. However, the clock monitor circuit if enabled remains active during HALT mode in order to ensure a clock monitor error if the device inadvertently enters the HALT mode as a result of a runaway program or power glitch. Power Save Modes The device offers the user two power save modes of operation: HALT and IDLE. In the HALT mode, all microcontroller activities are stopped. In the IDLE mode, the on-board oscillator circuitry the WATCHDOG logic, the Clock Monitor and timer T0 are active but all other microcontroller activities are stopped. In either mode, all on-board RAM, registers, I/O states, and timers (with the exception of T0) are unaltered. HALT MODE The device can be placed in the HALT mode by writing a “1” to the HALT flag (G7 data bit). All microcontroller activities, including the clock and timers, are stopped. The WATCHDOG logic is disabled during the HALT mode. However, the clock monitor circuitry if enabled remains active and will cause the WATCHDOG output pin (WDOUT) to go low. If the HALT mode is used and the user does not want to activate the WDOUT pin, the Clock Monitor should be disabled after the device comes out of reset (resetting the Clock Monitor control bit with the first write to the WDSVR register). In the HALT mode, the power requirements of the device are minimal and the applied voltage (VCC) may be decreased to Vr (Vr = 2.0V) without altering the state of the machine. The device supports three different ways of exiting the HALT mode. The first method of exiting the HALT mode is with the Multi-Input Wakeup feature on the L port. The second method is with a low to high transition on the CKO (G7) pin. This method precludes the use of the crystal clock configuration (since CKO becomes a dedicated output), and so may be used with an RC clock configuration. The third method of exiting the HALT mode is by pulling the RESET pin low. Since a crystal or ceramic resonator may be selected as the oscillator, the Wakeup signal is not allowed to start the chip running immediately since crystal oscillators and ceramic www.national.com tC 18 Power Save Modes Alternatively, the user can enter the IDLE mode with the IDLE Timer T0 interrupt disabled. In this case, the device will resume normal operation with the instruction immediately following the “Enter IDLE Mode” instruction. (Continued) IDLE MODE The device is placed in the IDLE mode by writing a “1” to the IDLE flag (G6 data bit). In this mode, all activities, except the associated on-board oscillator circuitry, the WATCHDOG logic, the clock monitor and the IDLE Timer T0, are stopped. The power supply requirements of the microcontroller in this mode of operation are typically around 30% of normal power requirement of the microcontroller. As with the HALT mode, the device can be returned to normal operation with a reset, or with a Multi-Input Wakeup from the L Port. The microcontroller may also be awakened from the IDLE mode after a selectable amount of time up to 65,536 instruction cycles, or 65.536 milliseconds with a 1 MHz instruction clock frequency. The IDLE timer period is selectable from one of five values, 4k, 8k, 16k, 32k or 64k instruction cycles. Selection of this value is made through the ITMR register. The user has the option of being interrupted with a transition on the thirteenth bit of the IDLE Timer T0. The interrupt can be enabled or disabled via the T0EN control bit. Setting the T0EN flag enables the interrupt and vice versa. The user can enter the IDLE mode with the Timer T0 interrupt enabled. In this case, when the T0PND bit gets set, the device will first execute the Timer T0 interrupt service routine and then return to the instruction following the “Enter Idle Mode” instruction. The IDLE timer cannot be started or stopped under software control, and it is not memory mapped, so it cannot be read or written by the software. Its state upon Reset is unknown. Therefore, if the device is put into the IDLE mode at an arbitrary time, it will stay in the IDLE mode for somewhere between 1 and the selected number of instruction cycles. Upon reset the ITMR register is cleared and selects the 4,096 instruction cycle tap of the Idle Timer. Note: It is necessary to program two NOP instructions following both the set HALT mode and set IDLE mode instructions. These NOP instructions are necessary to allow clock resynchronization following the HALT or IDLE modes. For more information on the IDLE Timer and its associated interrupt, see the description in the Timers Section. Multi-Input Wakeup The Multi-Input Wakeup feature is ued to return (wakeup) the device from either the HALT or IDLE modes. Alternately Multi-Input Wakeup/Interrupt feature may also be used to generate up to 8 edge selectable external interrupts. Figure 12 shows the Multi-Input Wakeup logic. DS100076-13 FIGURE 12. Multi-Input Wake Up Logic The user can select whether the trigger condition on the selected L Port pin is going to be either a positive edge (low to high transition) or a negative edge (high to low transition). This selection is made via the Reg: WKEDG, which is an 8-bit control register with a bit assigned to each L Port pin. Setting the control bit will select the trigger condition to be a negative edge on that particular L Port pin. Resetting the bit The Multi-Input Wakeup feature utilizes the L Port. The user selects which particular L port bit (or combination of L Port bits) will cause the device to exit the HALT or IDLE modes. The selection is done through the Reg: WKEN. The Reg: WKEN is an 8-bit read/write register, which contains a control bit for every L port bit. Setting a particular WKEN bit enables a Wakeup from the associated L port pin. 19 www.national.com Multi-Input Wakeup modes. In the other case, the device will first execute the interrupt service routine and then revert to normal operation. (See HALT MODE for clock option wakeup information.) (Continued) selects the trigger condition to be a positive edge. Changing an edge select entails several steps in order to avoid a pseudo Wakeup condition as a result of the edge change. First, the associated WKEN bit should be reset, followed by the edge select change in WKEDG. Next, the associated WKPND bit should be cleared, followed by the associated WKEN bit being re-enabled. An example may serve to clarify this procedure. Suppose we wish to change the edge select from positive (low going high) to negative (high going low) for L Port bit 5, where bit 5 has previously been enabled for an input interrupt. The program would be as follows: RBIT 5, WKEN ; Disable MIWU SBIT 5, WKEDG ; Change edge polarity RBIT 5, WKPND ; Reset pending flag SBIT 5, WKEN ; Enable MIWU A/D Converter The device contains an 8-channel, multiplexed input, successive approximation, Analog-to Digital converter. The device’s VCC and GND pins are used for voltage reference. OPERATING MODES The A/D converter supports ratiometric measurements. It supports both Single Ended and Differential modes of operation. Four specific analog channel selection modes are supported. These are as follows: Allow any specific channel to be selected at one time. The A/D converter performs the specific conversion requested and stops. Allow any specific channel to be scanned continuously. In other words, the user specifies the channel and the A/D converter scans it continuously. At any arbitrary time the user can immediately read the result of the last conversion. The user must wait for only the first conversion to complete. Allow any differential channel pair to be selected at one time. The A/D converter performs the specific differential conversion requested and stops. If the L port bits have been used as outputs and then changed to inputs with Multi-Input Wakeup/Interrupt, a safety procedure should also be followed to avoid inherited pseudo wakeup conditions. After the selected L port bits have been changed from output to input but before the associated WKEN bits are enabled, the associated edge select bits in WKEDG should be set or reset for the desired edge selects, followed by the associated WKPND bits being cleared. This same procedure should be used following reset, since the L port inputs are left floating as a result of reset. The occurrence of the selected trigger condition for Multi-Input Wakeup is latched into a pending register called WKPND. The respective bits of the WKPND register will be set on the occurrence of the selected trigger edge on the corresponding Port L pin. The user has the responsibility of clearing these pending flags. Since WKPND is a pending register for the occurrence of selected wakeup conditions, the device will not enter the HALT mode if any Wakeup bit is both enabled and pending. Consequently, the user has the responsibility of clearing the pending flags before attempting to enter the HALT mode. WKEN, WKPND and WKEDG are all read/write registers, and are cleared at reset. Allow any differential channel pair to be scanned continuously. In other words, the user specifies the differential channel pair and the A/D converter scans it continuously. At any arbitrary time the user can immediately read the result of the last differential conversion. The user must wait for only the first conversion to complete. The A/D converter is supported by two memory mapped registers, the result register and the mode control register. When the device is reset, the mode control register (ENAD) is cleared, the A/D is powered down and the A/D result register has unknown data. A/D Control Register The ENAD control register contains 3 bits for channel selection, 2 bits for prescaler selection, 2 bits for mode selection and a Busy bit. An A/D conversion is initiated by setting the ADBSY bit in the ENAD control register. The result of the conversion is available to the user in the A/D result register, ADRSLT, when ADBSY is cleared by the hardware on completion of the conversion. ENAD (Address 0xCB) PORT L INTERRUPTS Port L provides the user with an additional eight fully selectable, edge sensitive interrupts which are all vectored into the same service subroutine. The interrupt from Port L shares logic with the wake up circuitry. The register WKEN allows interrupts from Port L to be individually enabled or disabled. The register WKEDG specifies the trigger condition to be either a positive or a negative edge. Finally, the register WKPND latches in the pending trigger conditions. The GIE (Global Interrupt Enable) bit enables the interrupt function. A control flag, LPEN, functions as a global interrupt enable for Port L interrupts. Setting the LPEN flag will enable interrupts and vice versa. A separate global pending flag is not needed since the register WKPND is adequate. ADCH2 Bit 7 Since Port L is also used for waking the device out of the HALT or IDLE modes, the user can elect to exit the HALT or IDLE modes either with or without the interrupt enabled. If he elects to disable the interrupt, then the device will restart execution from the instruction immediately following the instruction that placed the microcontroller in the HALT or IDLE www.national.com 20 CHANNEL MODE PRESCALER SELECT SELECT SELECT ADCH1 ADCH0 ADMOD1 ADMOD0 PSC1 PSC0 BUSY ADBSY Bit 0 A/D Converter BUSY BIT The ADBSY bit of the ENAD register is used to control starting and stopping of the A/D conversion. When ADBSY is cleared, the prescale logic is disabled and the A/D clock is turned off. Setting the ADBSY bit starts the A/D clock and initiates a conversion based on the mode select value currently in the ENAD register. Normal completion of an A/D conversion clears the ADBSY bit and turns off the A/D converter. The ADBSY bit remains a one during continuous conversion. The user can stop continuous conversion by writing a zero to the ADBSY bit. If the user wishes to restart a conversion which is already in progress, this can be accomplished only by writing a zero to the ADBSY bit to stop the current conversion and then by writing a one to ADBSY to start a new conversion. This can be done in two consecutive instructions. (Continued) CHANNEL SELECT This 3-bit field selects one of eight channels to be the VIN+. The mode selection determines the VIN− input. Single Ended mode: Bit 7 Bit 6 Bit 5 Channel No. 0 0 0 0 0 0 1 1 0 1 0 2 0 1 1 3 1 0 0 4 1 0 1 5 1 1 0 6 1 1 1 7 ADC Operation Differential mode: Bit 7 Bit 6 Bit 5 Channel Pairs (+, −) 0 0 0 0, 1 0 0 1 1, 0 0 1 0 2, 3 0 1 1 3, 2 1 0 0 4, 5 1 0 1 5, 4 1 1 0 6, 7 1 1 1 7, 6 The A/D converter interface works as follows. Setting the ADBSY bit in the A/D control register ENAD initiates an A/D conversion. The conversion sequence starts at the beginning of the write to ENAD operation which sets ADBSY, thus powering up the A/D. At the first falling edge of the converter clock following the write operation, the sample signal turns on for seven clock cycles. If the A/D is in single conversion mode, the conversion complete signal from the A/D will generate a power down for the A/D converter and will clear the ADBSY bit in the ENAD register at the next instruction cycle boundary. If the A/D is in continuous mode, the conversion complete signal will restart the conversion sequence by deselecting the A/D for one converter clock cycle before starting the next sample. The A/D 8-bit result is immediately loaded into the A/D result register (ADRSLT) upon completion. Internal logic prevents transient data (resulting from the A/D writing a new result over an old one) being read from ADRSLT. Inadvertent changes to the ENAD register during conversion are prevented by the control logic of the A/D. Any attempt to write any bit of the ENAD Register except ADBSY, while ADBSY is a one, is ignored. ADBSY must be cleared either by completion of an A/D conversion or by the user before the prescaler, conversion mode or channel select values can be changed. After stopping the current conversion, the user can load different values for the prescaler, conversion mode or channel select and start a new conversion in one instruction. It is important for the user to realize that, when used in differential mode, only the positive input to the A/D converter is sampled and held. The negative input is constantly connected and should be held stable for the duration of the conversion. Failure to maintain a stable negative input will result in incorrect conversion. MODE SELECT This 2-bit field is used to select the mode of operation (single conversion, continuous conversions, differential, single ended) as shown in the following table. Bit 4 Bit 3 0 0 Single Ended mode, single conversion Mode 0 1 Single Ended mode, continuous scan of a single channel into the result register 1 0 Differential mode, single conversion 1 1 Differential mode, continuous scan of a channel pair into the result register PRESCALER SELECT This 2-bit field is used to select one of the four prescaler clocks for the A/D converter. The following table shows the various prescaler options. A/D Converter Clock Prescale Bit 2 Bit 1 Clock Select 0 0 Divide by 2 0 1 Divide by 4 1 0 Divide by 6 1 1 Divide by 12 PRESCALER The A/D Converter (A/D) contains a prescaler option that allows four different clock selections. The A/D clock frequency is equal to CKI divided by the prescaler value. Note that the prescaler value must be chosen such that the A/D clock falls within the specified range. The maximum A/D frequency is 1.67 MHz. This equates to a 600 ns A/D clock cycle. 21 www.national.com A/D Converter cause conversion errors. The clock lead should be kept away from the analog input line to reduce coupling. The A/D channel input pins do not have any internal output driver circuitry connected to them because this circuitry would load the analog input signals due to output buffer leakage current. Source impedances greater than 3 kΩ on the analog input lines will adversely affect the internal RC charging time during input sampling. As shown in Figure 13, the analog switch to the DAC array is closed only during the 7 A/D cycle sample time. Large source impedances on the analog inputs may result in the DAC array not being charged to the correct voltage levels, causing scale errors. If large source resistance is necessary, the recommended solution is to slow down the A/D clock speed in proportion to the source resistance. The A/D converter may be operated at the maximum speed for RS less than 3 kΩ. For RS greater than 3 kΩ, A/D clock speed needs to be reduced. For example, with RS = 6 kΩ, the A/D converter may be operated at half the maximum speed. A/D converter clock speed may be slowed down by either increasing the A/D prescaler divide-by or decreasing the CKI clock frquency. The A/D minimum clock speed is 100 kHz. (Continued) The A/D converter takes 17 A/D clock cycles to complete a conversion. Thus the minimum A/D conversion time for the device is 10.2 µs when a prescaler of 6 has been selected. The 17 A/D clock cycles needed for conversion consist of 1 cycle at the beginning for reset, 7 cycles for sampling, 8 cycles for converting, and 1 cycle for loading the result into the A/D result register (ADRSLT). This A/D result register is a read-only register. The user cannot write into ADRSLT. The ADBSY flag provides an A/D clock inhibit function, which saves power by powering down the A/D when it is not in use. Note: The A/D converter is also powered down when the device is in either the HALT or IDLE modes. If the A/D is running when the device enters the HALT or IDLE modes, the A/D powers down and then restarts the conversion with a corrupted sampled voltage (and thus an invalid result) when the device comes out of the HALT or IDLE modes. Analog Input and Source Resistance Considerations Figure 13 shows the A/D pin model in single ended mode. The differential mode has a similar A/D pin model. The leads to the analog inputs should be kept as short as possible. Both noise and digital clock coupling to an A/D input can DS100076-18 *The analog switch is closed only during the sample time. FIGURE 13. A/D Pin Model (Single Ended Mode) The Software trap has the highest priority while the default VIS has the lowest priority. Each of the 11 maskable inputs has a fixed arbitration ranking and vector. Interrupts INTRODUCTION Each device supports eleven vectored interrupts. Interrupt sources include Timer 0, Timer 1, Timer 2, Timer 3, Port L Wakeup, Software Trap, MICROWIRE/PLUS, and External Input. All interrupts force a branch to location 00FF Hex in program memory. The VIS instruction may be used to vector to the appropriate service routine from location 00FF Hex. www.national.com Figure 14 shows the Interrupt Block Diagram. 22 Interrupts (Continued) DS100076-14 FIGURE 14. Interrupt Block Diagram edged until the start of the next normally executed instruction is to be skipped, the skip is performed before the pending interrupt is acknowledged. At the start of interrupt acknowledgment, the following actions occur: 1. The GIE bit is automatically reset to zero, preventing any subsequent maskable interrupt from interrupting the current service routine. This feature prevents one maskable interrupt from interrupting another one being serviced. 2. The address of the instruction about to be executed is pushed onto the stack. 3. The program counter (PC) is loaded with 00FF Hex, causing a jump to that program memory location. The device requires seven instruction cycles to perform the actions listed above. If the user wishes to allow nested interrupts, the interrupts service routine may set the GIE bit to 1 by writing to the PSW register, and thus allow other maskable interrupts to interrupt the current service routine. If nested interrupts are allowed, caution must be exercised. The user must write the program in such a way as to prevent stack overflow, loss of saved context information, and other unwanted conditions. The interrupt service routine stored at location 00FF Hex should use the VIS instruction to determine the cause of the interrupt, and jump to the interrupt handling routine corresponding to the highest priority enabled and active interrupt. Alternately, the user may choose to poll all interrupt pending and enable bits to determine the source(s) of the interrupt. If more than one interrupt is active, the user’s program must decide which interrupt to service. Within a specific interrupt service routine, the associated pending bit should be cleared. This is typically done as early as possible in the service routine in order to avoid missing the next occurrence of the same type of interrupt event. Thus, if the same event occurs a second time, even while the first occurrence is still being serviced, the second occurrence will be serviced immediately upon return from the current interrupt routine. MASKABLE INTERRUPTS All interrupts other than the Software Trap are maskable. Each maskable interrupt has an associated enable bit and pending flag bit. The pending bit is set to 1 when the interrupt condition occurs. The state of the interrupt enable bit, combined with the GIE bit determines whether an active pending flag actually triggers an interrupt. All of the maskable interrupt pending and enable bits are contained in mapped control registers, and thus can be controlled by the software. A maskable interrupt condition triggers an interrupt under the following conditions: 1. The enable bit associated with that interrupt is set. 2. The GIE bit is set. 3. The device is not processing a non-maskable interrupt. (If a non-maskable interrupt is being serviced, a maskable interrupt must wait until that service routine is completed.) An interrupt is triggered only when all of these conditions are met at the beginning of an instruction. If different maskable interrupts meet these conditions simultaneously, the highest priority interrupt will be serviced first, and the other pending interrupts must wait. Upon Reset, all pending bits, individual enable bits, and the GIE bit are reset to zero. Thus, a maskable interrupt condition cannot trigger an interrupt until the program enables it by setting both the GIE bit and the individual enable bit. When enabling an interrupt, the user should consider whether or not a previously activated (set) pending bit should be acknowledged. If, at the time an interrupt is enabled, any previous occurrences of the interrupt should be ignored, the associated pending bit must be reset to zero prior to enabling the interrupt. Otherwise, the interrupt may be simply enabled; if the pending bit is already set, it will immediately trigger an interrupt. A maskable interrupt is active if its associated enable and pending bits are set. An interrupt is an asychronous event which may occur before, during, or after an instruction cycle. Any interrupt which occurs during the execution of an instruction is not acknowl- 23 www.national.com Interrupts The vector table should be filled by the user with the memory locations of the specific interrupt service routines. For example, if the Software Trap routine is located at 0310 Hex, then the vector location 0yFE and -0yFF should contain the data 03 and 10 Hex, respectively. When a Software Trap interrupt occurs and the VIS instruction is executed, the program jumps to the address specified in the vector table. (Continued) An interrupt service routine typically ends with an RETI instruction. This instruction sets the GIE bit back to 1, pops the address stored on the stack, and restores that address to the program counter. Program execution then proceeds with the next instruction that would have been executed had there been no interrupt. If there are any valid interrupts pending, the highest-priority interrupt is serviced immediately upon return from the previous interrupt. The interrupt sources in the vector table are listed in order of rank, from highest to lowest priority. If two or more enabled and pending interrupts are detected at the same time, the one with the highest priority is serviced first. Upon return from the interrupt service routine, the next highest-level pending interrupt is serviced. If the VIS instruction is executed, but no interrupts are enabled and pending, the lowest-priority interrupt vector is used, and a jump is made to the corresponding address in the vector table. This is an unusual occurrence, and may be the result of an error. It can legitimately result from a change in the enable bits or pending flags prior to the execution of the VIS instruction, such as executing a single cycle instruction which clears an enable flag at the same time that the pending flag is set. It can also result, however, from inadvertent execution of the VIS command outside of the context of an interrupt. The default VIS interrupt vector can be useful for applications in which time critical interrupts can occur during the servicing of another interrupt. Rather than restoring the program context (A, B, X, etc.) and executing the RETI instruction, an interrupt service routine can be terminated by returning to the VIS instruction. In this case, interrupts will be serviced in turn until no further interrupts are pending and the default VIS routine is started. After testing the GIE bit to ensure that execution is not erroneous, the routine should restore the program context and execute the RETI to return to the interrupted program. This technique can save up to fifty instruction cycles (tc), or more, (50µs at 10 MHz oscillator) of latency for pending interrupts with a penalty of fewer than ten instruction cycles if no further interrupts are pending. To ensure reliable operation, the user should always use the VIS instruction to determine the source of an interrupt. Although it is possible to poll the pending bits to detect the source of an interrupt, this practice is not recommended. The use of polling allows the standard arbitration ranking to be altered, but the reliability of the interrupt system is compromised. The polling routine must individually test the enable and pending bits of each maskable interrupt. If a Software Trap interrupt should occur, it will be serviced last, even though it should have the highest priority. Under certain conditions, a Software Trap could be triggered but not serviced, resulting in an inadvertent “locking out” of all maskable interrupts by the Software Trap pending flag. Problems such as this can be avoided by using VIS instruction. VIS INSTRUCTION The general interrupt service routine, which starts at address 00FF Hex, must be capable of handling all types of interrupts. The VIS instruction, together with an interrupt vector table, directs the device to the specific interrupt handling routine based on the cause of the interrupt. VIS is a single-byte instruction, typically used at the very beginning of the general interrupt service routine at address 00FF Hex, or shortly after that point, just after the code used for context switching. The VIS instruction determines which enabled and pending interrupt has the highest priority, and causes an indirect jump to the address corresponding to that interrupt source. The jump addresses (vectors) for all possible interrupts sources are stored in a vector table. The vector table may be as long as 32 bytes (maximum of 16 vectors) and resides at the top of the 256-byte block containing the VIS instruction. However, if the VIS instruction is at the very top of a 256-byte block (such as at 00FF Hex), the vector table resides at the top of the next 256-byte block. Thus, if the VIS instruction is located somewhere between 00FF and 01DF Hex (the usual case), the vector table is located between addresses 01E0 and 01FF Hex. If the VIS instruction is located between 01FF and 02DF Hex, then the vector table is located between addresses 02E0 and 02FF Hex, and so on. Each vector is 15 bits long and points to the beginning of a specific interrupt service routine somewhere in the 32 kbyte memory space. Each vector occupies two bytes of the vector table, with the higher-order byte at the lower address. The vectors are arranged in order of interrupt priority. The vector of the maskable interrupt with the lowest rank is located to 0yE0 (higher-order byte) and 0yE1 (lower-order byte). The next priority interrupt is located at 0yE2 and 0yE3, and so forth in increasing rank. The Software Trap has the highest rank and its vector is always located at 0yFE and 0yFF. The number of interrupts which can become active defines the size of the table. Table 4 shows the types of interrupts, the interrupt arbitration ranking, and the locations of the corresponding vectors in the vector table. www.national.com 24 Interrupts (Continued) TABLE 4. Interupt Vector Table Arbitration Ranking Vector (Note 32) Source Description Address Hi-Low Byte (1) Highest Software (2) Reserved INTR Instruction 0yFE–0yFF (3) External Pin G0 Edge (4) Timer T0 Underflow 0yF8–0yF9 (5) Timer T1 T1A/Underflow 0yF6–0yF7 (6) Timer T1 T1B 0yF4–0yF5 (7) MICROWIRE/PLUS BUSY Low 0yF2–0yF3 (8) Reserved 0yF0–0yF1 (9) Reserved 0yEE–0yEF (10) Reserved (11) Timer T2 T2A/Underflow (12) Timer T2 T2B 0yE8–0yE9 (13) Timer T3 T3A/Underflow 0yE6–0yE7 (14) Timer T3 T3B 0yE4–0yE5 (15) Port L/Wakeup Port L Edge 0yE2–0yE3 (16) Lowest Default VIS Instr. Execution 0yE0–0yE1 0yFC–0yFD 0yFA–0yFB 0yEC–0yED 0yEA–0yEB without Any Interrupts Note 32: y is a variable which represents the VIS block. VIS and the vector table must be located in the same 256-byte block except if VIS is located at the last address of a block. In this case, the table must be in the next block. vector of the active interrupt with the highest arbitration ranking. This vector is read from program memory and placed into the PC which is now pointed to the 1st instruction of the service routine of the active interrupt with the highest arbitration ranking. VIS Execution When the VIS instruction is executed it activates the arbitration logic. The arbitration logic generates an even number between E0 and FE (E0, E2, E4, E6 etc...) depending on which active interrupt has the highest arbitration ranking at the time of the 1st cycle of VIS is executed. For example, if the software trap interrupt is active, FE is generated. If the external interrupt is active and the software trap interrupt is not, then FA is generated and so forth. If the only active interrupt is software trap, than E0 is generated. This number replaces the lower byte of the PC. The upper byte of the PC remains unchanged. The new PC is therefore pointing to the Figure 15 illustrates the different steps performed by the VIS instruction. Figure 16 shows a flowchart for the VIS instruction. The non-maskable interrupt pending flag is cleared by the RPND (Reset Non-Maskable Pending Bit) instruction (under certain conditions) and upon RESET. 25 www.national.com Interrupts (Continued) DS100076-29 FIGURE 15. VIS Operation DS100076-30 FIGURE 16. VIS Flowchart www.national.com 26 Interrupts (Continued) Programming Example: External Interrupt WAIT: PSW CNTRL RBIT RBIT SBIT SBIT SBIT JP . . . .=0FF VIS =00EF =00EE 0,PORTGC 0,PORTGD IEDG, CNTRL EXEN, PSW GIE, PSW WAIT ; ; ; ; ; G0 pin configured Hi-Z Ext interrupt polarity; falling edge Enable the external interrupt Set the GIE bit Wait for external interrupt ; The interrupt causes a ; branch to address 0FF ; The VIS causes a branch to ;interrupt vector table . . . .=01FA .ADDRW SERVICE ; Vector table (within 256 byte ; of VIS inst.) containing the ext ; interrupt service routine . . INT_EXIT: SERVICE: RETI . . RBIT . . . JP EXPND, PSW INT_EXIT ; Interrupt Service Routine ; Reset ext interrupt pend. bit ; Return, set the GIE bit 27 www.national.com Interrupts flag; upon return to the first Software Trap routine, the STPND flag will have the wrong state. This will allow maskable interrupts to be acknowledged during the servicing of the first Software Trap. To avoid problems such as this, the user program should contain the Software Trap routine to perform a recovery procedure rather than a return to normal execution. Under normal conditions, the STPND flag is reset by a RPND instruction in the Software Trap service routine. If a programming error or hardware condition (brownout, power supply glitch, etc.) sets the STPND flag without providing a way for it to be cleared, all other interrupts will be locked out. To alleviate this condition, the user can use extra RPND instructions in the main program and in the WATCHDOG service routine (if present). There is no harm in executing extra RPND instructions in these parts of the program. (Continued) NON-MASKABLE INTERRUPT Pending Flag There is a pending flag bit associated with the non-maskable interrupt, called STPND. This pending flag is not memorymapped and cannot be accessed directly by the software. The pending flag is reset to zero when a device Reset occurs. When the non-maskable interrupt occurs, the associated pending bit is set to 1. The interrupt service routine should contain an RPND instruction to reset the pending flag to zero. The RPND instruction always resets the STPND flag. Software Trap The Software Trap is a special kind of non-maskable interrupt which occurs when the INTR instruction (used to acknowledge interrupts) is fetched from program memory and placed in the instruction register. This can happen in a variety of ways, usually because of an error condition. Some examples of causes are listed below. If the program counter incorrectly points to a memory location beyond the available program memory space, the nonexistent or unused memory location returns zeroes which is interpreted as the INTR instruction. If the stack is popped beyond the allowed limit (address 06F Hex), a 7FFF will be loaded into the PC, if this last location in program memory is unprogrammed or unavailable, a Software Trap will be triggered. A Software Trap can be triggered by a temporary hardware condition such as a brownout or power supply glitch. The Software Trap has the highest priority of all interrupts. When a Software Trap occurs, the STPND bit is set. The GIE bit is not affected and the pending bit (not accessible by the user) is used to inhibit other interrupts and to direct the program to the ST service routine with the VIS instruction. Nothing can interrupt a Software Trap service routine except for another Software Trap. The STPND can be reset only by the RPND instruction or a chip Reset. The Software Trap indicates an unusual or unknown error condition. Generally, returning to normal execution at the point where the Software Trap occurred cannot be done reliably. Therefore, the Software Trap service routine should reinitialize the stack pointer and perform a recovery procedure that restarts the software at some known point, similar to a device Reset, but not necessarily performing all the same functions as a device Reset. The routine must also execute the RPND instruction to reset the STPND flag. Otherwise, all other interrupts will be locked out. To the extent possible, the interrupt routine should record or indicate the context of the device so that the cause of the Software Trap can be determined. PORT L INTERRUPTS Port L provides the user with an additional eight fully selectable, edge sensitive interrupts which are all vectored into the same service subroutine. The interrupt from Port L shares logic with the wake up circuitry. The register WKEN allows interrupts from Port L to be individually enabled or disabled. The register WKEDG specifies the trigger condition to be either a positive or a negative edge. Finally, the register WKPND latches in the pending trigger conditions. The GIE (Global Interrupt Enable) bit enables the interrupt function. A control flag, LPEN, functions as a global interrupt enable for Port L interrupts. Setting the LPEN flag will enable interrupts and vice versa. A separate global pending flag is not needed since the register WKPND is adequate. Since Port L is also used for waking the device out of the HALT or IDLE modes, the user can elect to exit the HALT or IDLE modes either with or without the interrupt enabled. If he elects to disable the interrupt, then the device will restart execution from the instruction immediately following the instruction that placed the microcontroller in the HALT or IDLE modes. In the other case, the device will first execute the interrupt service routine and then revert to normal operation. (See HALT MODE for clock option wakeup information.) INTERRUPT SUMMARY The device uses the following types of interrupts, listed below in order of priority: 1. The Software Trap non-maskable interrupt, triggered by the INTR (00 opcode) instruction. The Software Trap is acknowledged immediately. This interrupt service routine can be interrupted only by another Software Trap. The Software Trap should end with two RPND instructions followed by a restart procedure. 2. Maskable interrupts, triggered by an on-chip peripheral block or an external device connected to the device. Under ordinary conditions, a maskable interrupt will not interrupt any other interrupt routine in progress. A maskable interrupt routine in progress can be interrupted by the non-maskable interrupt request. A maskable interrupt routine should end with an RETI instruction or, prior to restoring context, should return to execute the VIS instruction. This is particularly useful when exiting long interrupt service routiness if the time between interrupts is short. In this case the RETI instruction would only be executed when the default VIS routine is reached. If the user wishes to return to normal execution from the point at which the Software Trap was triggered, the user must first execute RPND, followed by RETSK rather than RETI or RET. This is because the return address stored on the stack is the address of the INTR instruction that triggered the interrupt. The program must skip that instruction in order to proceed with the next one. Otherwise, an infinite loop of Software Traps and returns will occur. Programming a return to normal execution requires careful consideration. If the Software Trap routine is interrupted by another Software Trap, the RPND instruction in the service routine for the second Software Trap will reset the STPND www.national.com 28 occur after coming out of reset, if the instruction cycle clock frequency has not reached a minimum specified value, including the case where the oscillator fails to start. The WDSVR register can be written to only once after reset and the key data (bits 5 through 1 of the WDSVR Register) must match to be a valid write. This write to the WDSVR register involves two irrevocable choices: (i) the selection of the WATCHDOG service window (ii) enabling or disabling of the Clock Monitor. Hence, the first write to WDSVR Register involves selecting or deselecting the Clock Monitor, select the WATCHDOG service window and match the WATCHDOG key data. Subsequent writes to the WDSVR register will compare the value being written by the user to the WATCHDOG service window value and the key data (bits 7 through 1) in the WDSVR Register. Table 5 shows the sequence of events that can occur. WATCHDOG The device contains a WATCHDOG and clock monitor. The WATCHDOG is designed to detect the user program getting stuck in infinite loops resulting in loss of program control or “runaway” programs. The Clock Monitor is used to detect the absence of a clock or a very slow clock below a specified rate on the CKI pin. The WATCHDOG consists of two independent logic blocks: WD UPPER and WD LOWER. WD UPPER establishes the upper limit on the service window and WD LOWER defines the lower limit of the service window. Servicing the WATCHDOG consists of writing a specific value to a WATCHDOG Service Register named WDSVR which is memory mapped in the RAM. This value is composed of three fields, consisting of a 2-bit Window Select, a 5-bit Key Data field, and the 1-bit Clock Monitor Select field. Table 5 shows the WDSVR register. The user must service the WATCHDOG at least once before the upper limit of the service window expires. The WATCHDOG may not be serviced more than once in every lower limit of the service window. The user may service the WATCHDOG as many times as wished in the time period between the lower and upper limits of the service window. The first write to the WDSVR Register is also counted as a WATCHDOG service. The WATCHDOG has an output pin associated with it. This is the WDOUT pin, on pin 1 of the port G. WDOUT is active low. The WDOUT pin is in the high impedance state in the inactive state. Upon triggering the WATCHDOG, the logic will pull the WDOUT (G1) pin low for an additional 16 tc–32 tc cycles after the signal level on WDOUT pin goes below the lower Schmitt trigger threshold. After this delay, the device will stop forcing the WDOUT output low. The WATCHDOG service window will restart when the WDOUT pin goes high. It is recommended that the user tie the WDOUT pin back to VCC through a resistor in order to pull WDOUT high. A WATCHDOG service while the WDOUT signal is active will be ignored. The state of the WDOUT pin is not guaranteed on reset, but if it powers up low then the WATCHDOG will time out and WDOUT will enter high impedance state. The Clock Monitor forces the G1 pin low upon detecting a clock frequency error. The Clock Monitor error will continue until the clock frequency has reached the minimum specified value, after which the G1 output will enter the high impedance TRI-STATE mode following 16 tc–32 tc clock cycles. The Clock Monitor generates a continual Clock Monitor error if the oscillator fails to start, or fails to reach the minimum specified frequency. The specification for the Clock Monitor is as follows: 1/tc > 10 kHz — No clock rejection. TABLE 5. WATCHDOG Service Register (WDSVR) Window Key Data Clock Select Monitor X X 0 1 1 0 0 Y 7 6 5 4 3 2 1 0 The lower limit of the service window is fixed at 2048 instruction cycles. Bits 7 and 6 of the WDSVR register allow the user to pick an upper limit of the service window. Table 6 shows the four possible combinations of lower and upper limits for the WATCHDOG service window. This flexibility in choosing the WATCHDOG service window prevents any undue burden on the user software. Bits 5, 4, 3, 2 and 1 of the WDSVR register represent the 5-bit Key Data field. The key data is fixed at 01100. Bit 0 of the WDSVR Register is the Clock Monitor Select bit. TABLE 6. WATCHDOG Service Window Select WDSVR WDSVR Bit 7 Bit 6 Clock Service Window Monitor (Lower-Upper Limits) 0 0 x 2048–8k tC Cycles 0 1 x 2048–16k tC Cycles 1 0 x 2048–32k tC Cycles 1 1 x 2048–64k tC Cycles x x 0 Clock Monitor Disabled x x 1 Clock Monitor Enabled Clock Monitor 1/tc < 10 Hz — Guaranteed clock rejection. The Clock Monitor aboard the device can be selected or deselected under program control. The Clock Monitor is guaranteed not to reject the clock if the instruction cycle clock (1/ tc) is greater or equal to 10 kHz. This equates to a clock input rate on CKI of greater or equal to 100 kHz. WATCHDOG AND CLOCK MONITOR SUMMARY The following salient points regarding the WATCHDOG and CLOCK MONITOR should be noted: • Both the WATCHDOG and CLOCK MONITOR detector circuits are inhibited during RESET. WATCHDOG Operation The WATCHDOG and Clock Monitor are disabled during reset. The device comes out of reset with the WATCHDOG armed, the WATCHDOG Window Select bits (bits 6, 7 of the WDSVR Register) set, and the Clock Monitor bit (bit 0 of the WDSVR Register) enabled. Thus, a Clock Monitor error will 29 • Following RESET, the WATCHDOG and CLOCK MONITOR are both enabled, with the WATCHDOG having the maximum service window selected. • The WATCHDOG service window and CLOCK MONITOR enable/disable option can only be changed once, during the initial WATCHDOG service following RESET. www.national.com WATCHDOG Operation The subroutine stack grows down for each call (jump to subroutine), interrupt, or PUSH, and grows up for each return or POP. The stack pointer is initialized to RAM location 06F Hex during reset. Consequently, if there are more returns than calls, the stack pointer will point to addresses 070 and 071 Hex (which are undefined RAM). Undefined RAM from addresses 070 to 07F (Segment 0), 140 to 17F (Segment 1), and all other segments (i.e., Segments 2 … etc.) is read as all 1’s, which in turn will cause the program to return to address 7FFF Hex. This is an undefined ROM location and the instruction fetched (all 0’s) from this location will generate a software interrupt signaling an illegal condition. (Continued) • The initial WATCHDOG service must match the key data value in the WATCHDOG Service register WDSVR in order to avoid a WATCHDOG error. • Subsequent WATCHDOG services must match all three data fields in WDSVR in order to avoid WATCHDOG errors. • The correct key data value cannot be read from the WATCHDOG Service register WDSVR. Any attempt to read this key data value of 01100 from WDSVR will read as key data value of all 0’s. • The WATCHDOG detector circuit is inhibited during both the HALT and IDLE modes. • The CLOCK MONITOR detector circuit is active during both the HALT and IDLE modes. Consequently, the device inadvertently entering the HALT mode will be detected as a CLOCK MONITOR error (provided that the CLOCK MONITOR enable option has been selected by the program). • With the single-pin R/C oscillator mask option selected and the CLKDLY bit reset, the WATCHDOG service window will resume following HALT mode from where it left off before entering the HALT mode. • With the crystal oscillator mask option selected, or with the single-pin R/C oscillator mask option selected and the CLKDLY bit set, the WATCHDOG service window will be set to its selected value from WDSVR following HALT. Consequently, the WATCHDOG should not be serviced for at least 2048 instruction cycles following HALT, but must be serviced within the selected window to avoid a WATCHDOG error. • The IDLE timer T0 is not initialized with RESET. • The user can sync in to the IDLE counter cycle with an IDLE counter (T0) interrupt or by monitoring the T0PND flag. The T0PND flag is set whenever the thirteenth bit of the IDLE counter toggles (every 4096 instruction cycles). The user is responsible for resetting the T0PND flag. • A hardware WATCHDOG service occurs just as the device exits the IDLE mode. Consequently, the WATCHDOG should not be serviced for at least 2048 instruction cycles following IDLE, but must be serviced within the selected window to avoid a WATCHDOG error. • Following RESET, the initial WATCHDOG service (where the service window and the CLOCK MONITOR enable/ disable must be selected) may be programmed anywhere within the maximum service window (65,536 instruction cycles) initialized by RESET. Note that this initial WATCHDOG service may be programmed within the initial 2048 instruction cycles without causing a WATCHDOG error. Thus, the chip can detect the following illegal conditions: 1. Executing from undefined ROM 2. Over “POP”ing the stack by having more returns than calls. When the software interrupt occurs, the user can re-initialize the stack pointer and do a recovery procedure before restarting (this recovery program is probably similar to that following reset, but might not contain the same program initialization procedures). MICROWIRE/PLUS MICROWIRE/PLUS is a serial synchronous communications interface. The MICROWIRE/PLUS capability enables the device to interface with any of National Semiconductor’s MICROWIRE peripherals (i.e. A/D converters, display drivers, E2PROMs etc.) and with other microcontrollers which support the MICROWIRE interface. It consists of an 8-bit serial shift register (SIO) with serial data input (SI), serial data output (SO) and serial shift clock (SK). Figure 17 shows a block diagram of the MICROWIRE/PLUS logic. DS100076-15 FIGURE 17. MICROWIRE/PLUS Block Diagram The shift clock can be selected from either an internal source or an external source. Operating the MICROWIRE/PLUS arrangement with the internal clock source is called the Master mode of operation. Similarly, operating the MICROWIRE/ PLUS arrangement with an external shift clock is called the Slave mode of operation. The CNTRL register is used to configure and control the MICROWIRE/PLUS mode. To use the MICROWIRE/PLUS, the MSEL bit in the CNTRL register is set to one. In the master mode, the SK clock rate is selected by the two bits, SL0 and SL1, in the CNTRL register. Table 8 details the different clock rates that may be selected. Detection of Illegal Conditions The device can detect various illegal conditions resulting from coding errors, transient noise, power supply voltage drops, runaway programs, etc. Reading of undefined ROM gets zeros. The opcode for software interrupt is zero. If the program fetches instructions from undefined ROM, this will force a software interrupt, thus signaling that an illegal condition has occurred. www.national.com 30 MICROWIRE/PLUS (Continued) TABLE 7. WATCHDOG Service Actions Key Window Clock Data Data Monitor Action Match Match Match Don’t Care Mismatch Don’t Care Valid Service: Restart Service Window Error: Generate WATCHDOG Output Mismatch Don’t Care Don’t Care Error: Generate WATCHDOG Output Don’t Care Don’t Care Mismatch Error: Generate WATCHDOG Output onto the G Port. The SK pin must be selected as an input and the SO pin is selected as an output pin by setting and resetting the appropriate bits in the Port G configuration register. Table 9 summarizes the settings required to enter the Slave mode of operation. TABLE 8. MICROWIRE/PLUS Master Mode Clock Selection SL1 SL0 0 0 2 x tc SK 0 1 4 x tc 1 x 8 x tc Where tc is the instruction cycle clock The user must set the BUSY flag immediately upon entering the Slave mode. This will ensure that all data bits sent by the Master will be shifted properly. After eight clock pulses the BUSY flag will be cleared and the sequence may be repeated. MICROWIRE/PLUS OPERATION Setting the BUSY bit in the PSW register causes the MICROWIRE/PLUS to start shifting the data. It gets reset when eight data bits have been shifted. The user may reset the BUSY bit by software to allow less than 8 bits to shift. If enabled, an interrupt is generated when eight data bits have been shifted. The device may enter the MICROWIRE/PLUS mode either as a Master or as a Slave. Figure 18 shows how two microcontroller devices and several peripherals may be interconnected using the MICROWIRE/PLUS arrangements. Alternate SK Phase Operation The device allows either the normal SK clock or an alternate phase SK clock to shift data in and out of the SIO register. In both the modes the SK is normally low. In the normal mode data is shifted in on the rising edge of the SK clock and the data is shifted out on the falling edge of the SK clock. The SIO register is shifted on each falling edge of the SK clock. In the alternate SK phase operation, data is shifted in on the falling edge of the SK clock and shifted out on the rising edge of the SK clock. A control flag, SKSEL, allows either the normal SK clock or the alternate SK clock to be selected. Resetting SKSEL causes the MICROWIRE/PLUS logic to be clocked from the normal SK signal. Setting the SKSEL flag selects the alternate SK clock. The SKSEL is mapped into the G6 configuration bit. The SKSEL flag will power up in the reset condition, selecting the normal SK signal. Warning: The SIO register should only be loaded when the SK clock is low. Loading the SIO register while the SK clock is high will result in undefined data in the SIO register. SK clock is normally low when not shifting. Setting the BUSY flag when the input SK clock is high in the MICROWIRE/PLUS slave mode may cause the current SK clock for the SIO shift register to be narrow. For safety, the BUSY flag should only be set when the input SK clock is low. TABLE 9. MICROWIRE/PLUS Mode Settings This table assumes that the control flag MSEL is set. MICROWIRE/PLUS Master Mode Operation In the MICROWIRE/PLUS Master mode of operation the shift clock (SK) is generated internally by the device. The MICROWIRE Master always initiates all data exchanges. The MSEL bit in the CNTRL register must be set to enable the SO and SK functions onto the G Port. The SO and SK pins must also be selected as outputs by setting appropriate bits in the Port G configuration register. Table 9 summarizes the bit settings required for Master mode of operation. G4 (SO) G5 (SK) G4 G5 Config. Bit Config. Bit Fun. Fun. 1 1 SO Int. MICROWIRE/PLUS SK Master 0 1 0 MICROWIRE/PLUS Slave Mode Operation In the MICROWIRE/PLUS Slave mode of operation the SK clock is generated by an external source. Setting the MSEL bit in the CNTRL register enables the SO and SK functions 31 1 0 0 Operation TRI- Int. MICROWIRE/PLUS STATE SK Master SO Ext. MICROWIRE/PLUS SK Slave TRI- Ext. MICROWIRE/PLUS STATE SK Slave www.national.com MICROWIRE/PLUS (Continued) DS100076-16 FIGURE 18. MICROWIRE/PLUS Application www.national.com 32 Memory Map Address Address Contents S/ADD REG All RAM, ports and registers (except A and PC) are mapped into data memory address space. Contents S/ADD REG xxDA Port C Input Pins (Read Only) xxDB Reserved for Port C xxDC Port D Reserved 0000 to 006F On-Chip RAM bytes (112 bytes) xxDD to xxDF 0070 to 007F Unused RAM Address Space (Reads As All Ones) xxE0 to xxE5 Reserved xxE6 Timer T1 Autoload Register T1RB Lower Byte xxE7 Timer T1 Autoload Register T1RB Upper Byte xx80 to xxAF Unused RAM Address Space (Reads Undefined Data) xxB0 Timer T3 Lower Byte xxB1 Timer T3 Upper Byte xxE8 ICNTRL Register xxB2 Timer T3 Autoload Register T3RA Lower Byte xxE9 MICROWIRE/PLUS Shift Register xxEA Timer T1 Lower Byte Timer T3 Autoload Register T3RA Upper Byte xxEB Timer T1 Upper Byte xxEC Timer T1 Autoload Register T1RA Lower Byte xxB3 xxB4 Timer T3 Autoload Register T3RB Lower Byte xxED xxB5 Timer T3 Autoload Register T3RB Upper Byte Timer T1 Autoload Register T1RA Upper Byte xxEE CNTRL Control Register xxB6 Timer T3 Control Register xxEF PSW Register xxB7 Comparator Select Register (CMPSL) xxF0 to FB On-Chip RAM, Mapped as Registers xxB8 to xxBF Reserved xxFC X Register xxC0 Timer T2 Lower Byte xxFD SP Register xxC1 Timer T2 Upper Byte xxFE B Register xxC2 Timer T2 Autoload Register T2RA Lower Byte xxFF S Register 0100 to 017F On-Chip RAM, 128 Bytes xxC3 Timer T2 Autoload Register T2RA Upper Byte xxC4 Timer T2 Autoload Register T2RB Lower Byte xxC5 Timer T2 Autoload Register T2RB Upper Byte xxC6 Timer T2 Control Register xxC7 WATCHDOG Service Register (Reg:WDSVR) xxC8 MIWU Edge Select Register (Reg:WKEDG) xxC9 MIWU Enable Register (Reg:WKEN) xxCA MIWU Pending Register (Reg:WKPND) xxCB Reserved xxCC Reserved xxCD to xxCF Reserved xxD0 Port L Data Register xxD1 Port L Configuration Register xxD2 Port L Input Pins (Read Only) xxD3 Reserved for Port L xxD4 Port G Data Register xxD5 Port G Configuration Register xxD6 Port G Input Pins (Read Only) xxD7 Port I Input Pins (Read Only) xxD8 Port C Data Register xxD9 Port C Configuration Register Reading memory locations 0070H–007FH (Segment 0) will return all ones. Reading unused memory locations 0080H–00AFH (Segment 0) will return undefined data. Reading memory locations from other unused Segments (i.e., Segment 2, Segment 3, … etc.) will return undefined data. 33 www.national.com Addressing Modes Indirect This mode is used with the JID instruction. The contents of the accumulator are used as a partial address (lower 8 bits of PC) for accessing a location in the program memory. The contents of this program memory location serve as a partial address (lower 8 bits of PC) for the jump to the next instruction. There are ten addressing modes, six for operand addressing and four for transfer of control. OPERAND ADDRESSING MODES Register Indirect This is the “normal” addressing mode. The operand is the data memory addressed by the B pointer or X pointer. Register Indirect (with auto post increment or decrement of pointer) Note: The VIS is a special case of the Indirect Transfer of Control addressing mode, where the double byte vector associated with the interrupt is transferred from adjacent addresses in the program memory into the program counter (PC) in order to jump to the associated interrupt service routine. This addressing mode is used with the LD and X instructions. The operand is the data memory addressed by the B pointer or X pointer. This is a register indirect mode that automatically post increments or decrements the B or X register after executing the instruction. Direct The instruction contains an 8-bit address field that directly points to the data memory for the operand. Immediate The instruction contains an 8-bit immediate field as the operand. Short Immediate This addressing mode is used with the Load B Immediate instruction. The instruction contains a 4-bit immediate field as the operand. Indirect Instruction Set Register and Symbol Definition Registers This addressing mode is used with the LAID instruction. The contents of the accumulator are used as a partial address (lower 8 bits of PC) for accessing a data operand from the program memory. A 8-Bit Accumulator Register B 8-Bit Address Register X 8-Bit Address Register S 8-Bit Segment Register SP 8-Bit Stack Pointer Register PC 15-Bit Program Counter Register PU Upper 7 Bits of PC PL Lower 8 Bits of PC C 1 Bit of PSW Register for Carry HC 1 Bit of PSW Register for Half Carry GIE 1 Bit of PSW Register for Global Interrupt Enable VU Interrupt Vector Upper Byte VL Interrupt Vector Lower Byte [B] Memory Indirectly Addressed by B Register [X] Memory Indirectly Addressed by X Register MD Direct Addressed Memory Mem Direct Addressed Memory or [B] Absolute This mode is used with the JMP and JSR instructions, with the instruction field of 12 bits replacing the lower 12 bits of the program counter (PC). This allows jumping to any location in the current 4k program memory segment. Meml Direct Addressed Memory or [B] or Immediate Data Imm 8-Bit Immediate Data Reg Register Memory: Addresses F0 to FF (Includes B, X and SP) Absolute Long This mode is used with the JMPL and JSRL instructions, with the instruction field of 15 bits replacing the entire 15 bits of the program counter (PC). This allows jumping to any location up to 32k in the program memory space. Bit ← Bit Number (0 to 7) ↔ Exchanged with TRANSFER OF CONTROL ADDRESSING MODES Relative This mode is used for the JP instruction, with the instruction field being added to the program counter to get the new program location. JP has a range from −31 to +32 to allow a 1-byte relative jump (JP + 1 is implemented by a NOP instruction). There are no “pages” when using JP, since all 15 bits of PC are used. www.national.com Symbols 34 Loaded with Instruction Set (Continued) INSTRUCTION SET A ←A + Meml A ←A + Meml + C, C← Carry HC ←Half Carry ADD A,Meml ADD ADC A,Meml ADD with Carry SUBC A,Meml Subtract with Carry A ←A − MemI + C, C←Carry HC ←Half Carry A ←A and Meml AND A,Meml Logical AND ANDSZ A,Imm Logical AND Immed., Skip if Zero Skip next if (A and Imm) = 0 OR A,Meml Logical OR XOR A,Meml Logical EXclusive OR A ←A or Meml A ←A xor Meml IFEQ MD,Imm IF EQual IFEQ A,Meml IF EQual Compare MD and Imm, Do next if MD = Imm Compare A and Meml, Do next if A = Meml IFNE A,Meml IF Not Equal Compare A and Meml, Do next if A ≠ Meml IFGT A,Meml IF Greater Than Compare A and Meml, Do next if A > Meml Do next if lower 4 bits of B ≠ Imm IFBNE # If B Not Equal DRSZ Reg Decrement Reg., Skip if Zero SBIT #,Mem Set BIT Reg ←Reg − 1, Skip if Reg = 0 1 to bit, Mem (bit = 0 to 7 immediate) RBIT #,Mem Reset BIT 0 to bit, Mem IFBIT #,Mem IF BIT If bit in A or Mem is true do next instruction Reset PeNDing Flag Reset Software Interrupt Pending Flag RPND X A,Mem EXchange A with Memory A↔Mem X A,[X] EXchange A with Memory [X] LD A,Meml LoaD A with Memory A ↔[X] A ←Meml LD A,[X] LoaD A with Memory [X] LD B,Imm LoaD B with Immed. LD Mem,Imm LoaD Memory Immed Mem ←Imm LD Reg,Imm LoaD Register Memory Immed. Reg ←Imm A↔[B], (B ←B ± 1) A ←[X] B ←Imm X A, [B ± ] EXchange A with Memory [B] X A, [X ± ] EXchange A with Memory [X] LD A, [B ± ] LoaD A with Memory [B] LD A, [X ± ] LoaD A with Memory [X] A←[X], (X←X ± 1) LD [B ± ],Imm LoaD Memory [B] Immed. CLR A CLeaR A [B] ←Imm, (B←B ± 1) A←0 INC A INCrement A DEC A DECrement A LAID A↔[X], (X ←X ± 1) A←[B], (B←B ± 1) A←A + 1 A←A − 1 A←ROM (PU,A) Load A InDirect from ROM DCOR A Decimal CORrect A RRC A Rotate A Right thru C A←BCD correction of A (follows ADC, SUBC) C →A7→… →A0→C RLC A Rotate A Left thru C C←A7←…←A0←C SWAP A SWAP nibbles of A SC Set C RC Reset C A7…A4↔A3…A0 C←1, HC ←1 C←0, HC ←0 IFC IF C IF C is true, do next instruction IFNC IF Not C If C is not true, do next instruction SP←SP + 1, A←[SP] POP A POP the stack into A PUSH A PUSH A onto the stack VIS [SP]←A, SP←SP − 1 PU ←[VU], PL ←[VL] Vector to Interrupt Service Routine JMPL Addr. Jump absolute Long JMP Addr. Jump absolute PC ←ii (ii = 15 bits, 0 to 32k) PC9…0 ←i (i = 12 bits) JP Disp. Jump relative short PC ←PC + r (r is −31 to +32, except 1) 35 www.national.com Instruction Set (Continued) INSTRUCTION SET (Continued) JSRL Addr. Jump SubRoutine Long JSR Addr Jump SubRoutine JID Jump InDirect RET RETurn from subroutine RETSK RETurn and SKip RETI RETurn from Interrupt INTR Generate an Interrupt NOP No OPeration www.national.com [SP] ←PL, [SP−1]←PU,SP−2, PC ←ii [SP] ← PL, [SP−1]←PU,SP−2, PC9…0←i PL←ROM (PU,A) SP + 2, PL ← [SP], PU ← [SP−1] SP + 2, PL ←[SP],PU ← [SP−1] SP + 2, PL ←[SP],PU ←[SP−1],GIE ←1 [SP] ←PL, [SP−1]←PU, SP−2, PC ←0FF PC ← PC + 1 36 Instruction Execution Time Instructions Using A & C Most instructions are single byte (with immediate addressing mode instructions taking two bytes). CLRA 1/1 INCA 1/1 Most single byte instructions take one cycle time to execute. See the BYTES and CYCLES per INSTRUCTION table for details. Bytes and Cycles per Instruction DECA 1/1 The following table shows the number of bytes and cycles for each instruction in the format of byte/cycle. Arithmetic and Logic Instructions [B] ADD 1/1 Direct Immed. 3/4 2/2 ADC 1/1 3/4 2/2 SUBC 1/1 3/4 2/2 AND 1/1 3/4 2/2 LAID 1/3 DCOR 1/1 RRCA 1/1 RLCA 1/1 SWAPA 1/1 SC 1/1 RC 1/1 IFC 1/1 IFNC 1/1 PUSHA 1/3 POPA 1/3 ANDSZ 2/2 OR 1/1 3/4 2/2 XOR 1/1 3/4 2/2 IFEQ 1/1 3/4 2/2 IFNE 1/1 3/4 2/2 JMPL 3/4 IFGT 1/1 3/4 2/2 JMP 2/3 IFBNE 1/1 JP 1/3 Transfer of Control Instructions 1/3 JSRL SBIT 1/1 3/4 JSR 2/5 RBIT 1/1 3/4 JID 1/3 IFBIT 1/1 3/4 VIS 1/5 DRSZ RPND 1/1 3/5 RET 1/5 RETSK 1/5 RETI 1/5 INTR 1/7 NOP 1/1 Memory Transfer Instructions Register Direct Immed. Indirect [B] [X] X A, (Note *NO TARGET FOR FNXref NS7829*) 1/1 1/3 2/3 LD A, (Note *NO TARGET FOR FNXref NS7829*) 1/1 1/3 2/3 2/2 LD B, Imm 1/1 LD B, Imm 2/2 LD Mem, Imm 2/2 Register Indirect Auto Incr. & Decr. 3/3 LD Reg, Imm 2/3 IFEQ MD, Imm 3/3 [B+, B−] [X+, X−] 1/2 1/3 1/2 1/3 (IF B < 16) (IF B > 15) 2/2 Note 33: = > Memory location addressed by B or X or directly. 37 www.national.com www.national.com 38 JP−18 JP−17 JP−16 JP−2 JP−1 JP−0 LD 0FF, #i LD 0FE, #i LD 0FD, #i LD 0FC, #i LD 0FB, #i LD 0FA, #i LD 0F9, #i LD 0F8, #i LD 0F7, #i LD 0F6, #i LD 0F5, #i LD 0F4, #i LD 0F3, #i LD 0F2, #i LD 0F1, #i LD 0F0, #i D DRSZ 0FF DRSZ 0FE DRSZ 0FD DRSZ 0FC DRSZ 0FB DRSZ 0FA DRSZ 0F9 DRSZ 0F8 DRSZ 0F7 DRSZ 0F6 DRSZ 0F5 DRSZ 0F4 DRSZ 0F3 DRSZ 0F2 DRSZ 0F1 DRSZ 0F0 C B * LD A,[X] DIR LD Md,#i LD A,[X−] LD A,[X+] IFNE A,[B] NOP * X A,[X] RPND VIS X A,[X−] X A,[X+] * RRCA Where, i is the immediate data Md is a directly addressed memory location * is an unused opcode The opcode 60 Hex is also the opcode for IFBIT #i,A JP−19 JP−3 JP−24 JP−8 JP−20 JP−25 JP−9 JP−4 JP−26 JP−10 JP−21 JP−27 JP−11 JP−5 JP−28 JP−12 JP−22 JP−29 JP−13 JP−6 JP−30 JP−14 JP−23 JP−31 JP−15 JP−7 E F Opcode Table OR A,#i XOR A,#i AND A,#i ADD A,#i IFGT A,#i IFEQ A,#i SUBC A, #i ADC A,#i 9 LD [B−],#i LD [B+],#i IFNE A,#i * LD A,[B] JSRL LD B,#i LD [B],#i LD A,Md JMPL X A,Md LD A,[B−] LD A,[B+] IFEQ Md,#i RLCA LD A,#i * X A,[B] JID LAID X A,[B−] X A,[B+] SC RC A RETI RET 6 CLRA * * * 5 LD B,#0B LD B,#0C LD B,#0D LD B,#0E LD B,#0F SBIT 7,[B] SBIT 6,[B] SBIT 5,[B] SBIT 4,[B] SBIT 3,[B] SBIT 2,[B] SBIT 1,[B] SBIT 0,[B] RBIT 7,[B] RBIT 6,[B] RBIT 5,[B] RBIT 4,[B] RBIT 3,[B] RBIT 2,[B] RBIT 1,[B] RBIT 0,[B] IFBIT PUSHA 7,[B] IFBIT DCORA 6,[B] LD B,#00 LD B,#01 LD B,#02 LD B,#03 LD B,#04 LD B,#05 LD B,#06 LD B,#07 LD B,#08 LD B,#09 IFBIT SWAPA LD 5,[B] B,#0A IFBIT 4,[B] IFBIT 3,[B] IFBIT 2,[B] IFBIT 1,[B] IFBIT ANDSZ 0,[B] A, #i 7 Upper Nibble RETSK POPA DECA INCA IFNC IFC OR A,[B] XOR A,[B] AND A,[B] ADD A,[B] IFGT A,[B] IFEQ A,[B] SUBC A,[B] ADC A,[B] 8 4 IFBNE 0F IFBNE 0E IFBNE 0D IFBNE 0C IFBNE 0B IFBNE 0A IFBNE 9 IFBNE 8 IFBNE 7 IFBNE 6 IFBNE 5 IFBNE 4 IFBNE 3 IFBNE 2 IFBNE 1 IFBNE 0 3 2 1 0 8 7 6 5 4 3 2 1 0 JMP JP+26 JP+10 9 x900–x9FF JMP JP+25 JP+9 x800–x8FF JMP JP+24 JP+8 x700–x7FF JMP JP+23 JP+7 x600–x6FF JMP JP+22 JP+6 x500–x5FF JMP JP+21 JP+5 x400–x4FF JMP JP+20 JP+4 x300–x3FF JMP JP+19 JP+3 x200–x2FF JMP JP+18 JP+2 x100–x1FF JMP JP+17 INTR x000–x0FF JSR JMP JP+32 JP+16 F xF00–xFFF xF00–xFFF JSR JMP JP+31 JP+15 E xE00–xEFF xE00–xEFF JSR JMP JP+30 JP+14 D xD00–xDFF xD00–xDFF JSR JMP JP+29 JP+13 C xC00–xCFF xC00–xCFF JSR JMP JP+28 JP+12 B xB00–xBFF xB00–xBFF JSR JMP JP+27 JP+11 A xA00–xAFF xA00–xAFF JSR x900–x9FF JSR x800–x8FF JSR x700–x7FF JSR x600–x6FF JSR x500–x5FF JSR x400–x4FF JSR x300–x3FF JSR x200–x2FF JSR x100–x1FF JSR x000–x0FF Lower Nibble COP8 Integrated Software/Hardware Design Development Kits Mask Options The mask programmable options are shown below. The options are programmed at the same time as the ROM pattern submission. • OPTION 1: CLOCK CONFIGURATION = 1 Crystal Oscillator (CKI/10) G7 (CKO) is clock generator output to crystal/resonator CKI is the clock input = 2 Single-pin RC controlled oscillator (CKI/10) G7 is available as a HALT restart and/or general purpose input OPTION 2: HALT = 1 Enable HALT mode = 2 Disable HALT mode OPTION 3: BONDING = 1 44-Pin PLCC • COP8-DM: Moderate cost Debug Module from MetaLink. A Windows based, real-time in-circuit emulation tool with COP8 device programmer. Includes COP8-NSDEV, DriveWay COP8 Demo, MetaLink Debugger, power supply, emulation cables and adapters. COP8 Development Languages and Environments Development Tools Support OVERVIEW National is engaged with an international community of independent 3rd party vendors who provide hardware and software development tool support. Through National’s interaction and guidance, these tools cooperate to form a choice of solutions that fits each developer’s needs. This section provides a summary of the tool and development kits currently available. Up-to-date information, selection guides, free tools, demos, updates, and purchase information can be obtained at our web site at: www.national.com/cop8. • COP8-NSASM: Free COP8 Assembler v5 for Win32. Macro assembler, linker, and librarian for COP8 software development. Supports all COP8 devices. (DOS/Win16 v4.10.2 available with limited support). (Compatible with WCOP8 IDE, COP8C, and DriveWay COP8). • COP8-NSDEV: Very low cost Software Development Package for Windows. An integrated development environment for COP8, including WCOP8 IDE, COP8NSASM, COP8-MLSIM. • COP8C: Moderately priced C Cross-Compiler and Code Development System from Byte Craft (no code limit). Includes BCLIDE (Byte Craft Limited Integrated Development Environment) for Win32, editor, optimizing C CrossCompiler, macro cross assembler, BC-Linker, and MetaLink tools support. (DOS/SUN versions available; Compiler is installable under WCOP8 IDE; Compatible with DriveWay COP8). • EWCOP8-KS: Very Low cost ANSI C-Compiler and Embedded Workbench from IAR (Kickstart version: COP8Sx/Fx only with 2k code limit; No FP). A fully integrated Win32 IDE, ANSI C-Compiler, macro assembler, editor, linker, Liberian, C-Spy simulator/debugger, PLUS MetaLink EPU/DM emulator support. • EWCOP8-AS: Moderately priced COP8 Assembler and Embedded Workbench from IAR (no code limit). A fully integrated Win32 IDE, macro assembler, editor, linker, librarian, and C-Spy high-level simulator/debugger with I/O and interrupts support. (Upgradeable with optional C-Compiler and/or MetaLink Debugger/Emulator support). • EWCOP8-BL: Moderately priced ANSI C-Compiler and Embedded Workbench from IAR (Baseline version: All COP8 devices; 4k code limit; no FP). A fully integrated Win32 IDE, ANSI C-Compiler, macro assembler, editor, linker, librarian, and C-Spy high-level simulator/debugger. (Upgradeable; CWCOP8-M MetaLink tools interface support optional). • EWCOP8: Full featured ANSI C-Compiler and Embedded Workbench for Windows from IAR (no code limit). A fully integrated Win32 IDE, ANSI C-Compiler, macro assembler, editor, linker, librarian, and C-Spy high-level simulator/debugger. (CWCOP8-M MetaLink tools interface support optional). • EWCOP8-M: Full featured ANSI C-Compiler and Embedded Workbench for Windows from IAR (no code limit). A fully integrated Win32 IDE, ANSI C-Compiler, macro assembler, editor, linker, librarian, C-Spy high-level simulator/debugger, PLUS MetaLink debugger/hardware interface (CWCOP8-M). SUMMARY OF TOOLS COP8 Evaluation Tools • COP8–NSEVAL: Free Software Evaluation package for Windows. A fully integrated evaluation environment for COP8, including versions of WCOP8 IDE (Integrated Development Environment), COP8-NSASM, COP8-MLSIM, COP8C, DriveWay™ COP8, Manuals, and other COP8 information. • COP8–MLSIM: Free Instruction Level Simulator tool for Windows. For testing and debugging software instructions only (No I/O or interrupt support). • COP8–EPU: Very Low cost COP8 Evaluation & Programming Unit. Windows based evaluation and hardware-simulation tool, with COP8 device programmer and erasable samples. Includes COP8-NSDEV, Driveway COP8 Demo, MetaLink Debugger, I/O cables and power supply. • COP8–EVAL-ICUxx: Very Low cost evaluation and design test board for COP8ACC and COP8SGx Families, from ICU. Real-time environment with add-on A/D, D/A, and EEPROM. Includes software routines and reference designs. • Manuals, Applications Notes, Literature: Available free from our web site at: www.national.com/cop8. COP8-EPU: Very Low cost Evaluation & Programming Unit. Windows based development and hardwaresimulation tool for COPSx/xG families, with COP8 device programmer and samples. Includes COP8-NSDEV, Driveway COP8 Demo, MetaLink Debugger, cables and power supply. 39 www.national.com Development Tools Support COP8 Real-Time Emulation Tools • COP8-DM: MetaLink Debug Module. A moderately priced real-time in-circuit emulation tool, with COP8 device programmer. Includes COP8-NSDEV, DriveWay COP8 Demo, MetaLink Debugger, power supply, emulation cables and adapters. • IM-COP8: MetaLink iceMASTER ® . A full featured, realtime in-circuit emulator for COP8 devices. Includes MetaLink Windows Debugger, and power supply. Packagespecific probes and surface mount adaptors are ordered separately. COP8 Device Programmer Support • MetaLink’s EPU and Debug Module include development device programming capability for COP8 devices. • Third-party programmers and automatic handling equipment cover needs from engineering prototype and pilot production, to full production environments. • Factory programming available for high-volume requirements. (Continued) COP8 Productivity Enhancement Tools • WCOP8 IDE: Very Low cost IDE (Integrated Development Environment) from KKD. Supports COP8C, COP8NSASM, COP8-MLSIM, DriveWay COP8, and MetaLink debugger under a common Windows Project Management environment. Code development, debug, and emulation tools can be launched from the project window framework. • DriveWay-COP8: Low cost COP8 Peripherals Code Generation tool from Aisys Corporation. Automatically generates tested and documented C or Assembly source code modules containing I/O drivers and interrupt handlers for each on-chip peripheral. Application specific code can be inserted for customization using the integrated editor. (Compatible with COP8-NSASM, COP8C, and WCOP8 IDE.) • COP8-UTILS: Free set of COP8 assembly code examples, device drivers, and utilities to speed up code development. • COP8-MLSIM: Free Instruction Level Simulator tool for Windows. For testing and debugging software instructions only (No I/O or interrupt support). TOOLS ORDERING NUMBERS FOR THE COP888GD FAMILY DEVICES Vendor National Tools COP8-NSEVAL Order Number COP8-NSEVAL Cost Free Notes Web site download COP8-NSASM COP8-NSASM Free Included in EPU and DM. Web site download COP8-MLSIM COP8-MLSIM Free Included in EPU and DM. Web site download COP8-NSDEV COP8-NSDEV VL Included in EPU and DM. Order CD from website COP8-EPU Not available for this device COP8-DM Contact MetaLink Development Devices COP87L84GD/RD VL 16k or 32k OTP devices. IM-COP8 MetaLink COP8-EPU Contact MetaLink Not available for this device COP8-DM DM4-COP8-888GD (10 MHz), plus PS-10, plus DM-COP8/xxx (ie. 28D) M Included p/s (PS-10), target cable of choice (DIP or PLCC; i.e. DM-COP8/40D), 16/20/28/40 DIP/SO and 44 PLCC programming sockets. Add target adapter (if needed) DM Target Adapters MHW-CONV39 L DM target converters for 28SO IM-COP8 IM-COP8-AD-464 (-220) (10 MHz maximum) H Base unit 10 MHz; -220 = 220V; add probe card (required) and target adapter (if needed); included software and manuals IM Probe Card PC-888GD40DW-AD-10 M 10 MHz 40 DIP probe card; 2.5V to 6.0V PC-888GD44PW-AD-10 M 10 MHz 44 PLCC probe card; 2.5V to 6.0V Included in EPU and DM ICU COP8-EVAL Not available for this device KKD WCOP8-IDE WCOP8-IDE VL IAR EWCOP8-xx See summary above L-H Included all software and manuals Byte Craft COP8C COP8C M Included all software and manuals Aisys DriveWay COP8 DriveWay COP8 L Included all software and manuals www.national.com 40 Development Tools Support OTP Programmers (Continued) Contact vendors L-H For approved programmer listings and vendor information, go to our OTP support page at: www.national.com/cop8 Cost: Free; VL = < $100; L = $100 - $300; M = $300 - $1k; H = $1k - $3k; VH = $3k - $5k WHERE TO GET TOOLS Tools are ordered directly from the following vendors. Please go to the vendor’s web site for current listings of distributors. Vendor Aisys Home Office Electronic Sites U.S.A.: Santa Clara, CA www.aisysinc.com 1-408-327-8820 [email protected] Other Main Offices Distributors fax: 1-408-327-8830 Byte Craft U.S.A. www.bytecraft.com 1-519-888-6911 info @bytecraft.com Distributors fax: 1-519-746-6751 IAR Sweden: Uppsala www.iar.se U.S.A.: San Francisco +46 18 16 78 00 [email protected] 1-415-765-5500 fax: +46 18 16 78 38 [email protected] fax: 1-415-765-5503 [email protected] U.K.: London [email protected] +44 171 924 33 34 fax: +44 171 924 53 41 Germany: Munich +49 89 470 6022 fax: +49 89 470 956 ICU Sweden: Polygonvaegen www.icu.se Switzeland: Hoehe +46 8 630 11 20 [email protected] +41 34 497 28 20 fax: +46 8 630 11 70 support @icu.ch fax: +41 34 497 28 21 KKD Denmark: www.kkd.dk MetaLink U.S.A.: Chandler, AZ www.metaice.com Germany: Kirchseeon 1-800-638-2423 sales @metaice.com 80-91-5696-0 fax: 1-602-926-1198 support @metaice.com fax: 80-91-2386 National bbs: 1-602-962-0013 [email protected] www.metalink.de Distributors Worldwide U.S.A.: Santa Clara, CA www.national.com/cop8 Europe: +49 (0) 180 530 8585 1-800-272-9959 support @nsc.com fax: +49 (0) 180 530 8586 fax: 1-800-737-7018 europe.support @nsc.com Distributors Worldwide Customer Support The following companies have approved COP8 programmers in a variety of configurations. Contact your local office or distributor. You can link to their web sites and get the latest listing of approved programmers from National’s COP8 OTP Support page at: www.national.com/cop8. Complete product information and technical support is available from National’s customer response centers, and from our on-line COP8 customer support sites. Advantech; Advin; BP Microsystems; Data I/O; Hi-Lo Systems; ICE Technology; Lloyd Research; Logical Devices; MQP; Needhams; Phyton; SMS; Stag Programmers; System General; Tribal Microsystems; Xeltek. 41 www.national.com COP888GD 8-Bit CMOS ROM Based Microcontrollers with 16k Memory and 8-Channel A/D Physical Dimensions inches (millimeters) unless otherwise noted Plastic Leaded Chip Carrier (V) Order Number COP888GD-XXX/V or COP988GD-XXX/V NS Package Number V44A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: [email protected] www.national.com National Semiconductor Europe Fax: +49 (0) 1 80-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 1 80-530 85 85 English Tel: +49 (0) 1 80-532 78 32 Français Tel: +49 (0) 1 80-532 93 58 Italiano Tel: +49 (0) 1 80-534 16 80 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: [email protected] National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.