AT89LV55 - Mature

Features
• Compatible with MCS®-51 Products
• 20K Bytes of Reprogrammable Flash Memory
•
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•
•
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– Endurance: 1,000 Write/Erase Cycles
Fully Static Operation: 0 Hz to 12 MHz
Three-level Program Memory Lock
256 x 8-bit Internal RAM
32 Programmable I/O Lines
Three 16-bit Timer/Counters
Eight Interrupt Sources
Low-power Idle and Power-down Modes
2.7V to 6.0V Operating Range
1. Description
The AT89LV55 is a low-voltage, low-power CMOS 8-bit microcontroller with 20K bytes
of Flash programmable and erasable read-only memory. The device is manufactured
using Atmel’s high-density nonvolatile memory technology and is compatible with the
industry-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed. By combining a versatile 8-bit CPU with Flash on
a monolithic chip, the Atmel AT89LV55 is a powerful microcontroller which provides a
highly-flexible and cost-effective solution to many embedded control applications.
The AT89LV55 provides the following standard features: 20K bytes of Flash,
256 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-level
interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In
addition, the AT89LV55 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode
stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down Mode saves the RAM contents but
freezes the oscillator, disabling all other chip functions until the next hardware reset.
The low-voltage option saves power and operates with a 2.7-volt power supply.
8-bit
Microcontroller
with 20K Bytes
Flash
AT89LV55
Not Recommended
for New Designs.
Use AT89C51RC2.
0811E–MICRO–9/08
2. Pin Configurations
2.1
44A – 44-lead TQFP
2.2
40P6 – 40-lead PDIP
2.3
44J – 44-lead PLCC
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0811E–MICRO–9/08
AT89LV55
3. Block Diagram
P0.0 - P0.7
P2.0 - P2.7
PORT 0 DRIVERS
PORT 2 DRIVERS
VCC
GND
RAM ADDR.
REGISTER
B
REGISTER
PORT 0
LATCH
RAM
PORT 2
LATCH
FLASH
STACK
POINTER
ACC
PROGRAM
ADDRESS
REGISTER
BUFFER
TMP2
TMP1
PC
INCREMENTER
ALU
INTERRUPT, SERIAL PORT,
AND TIMER BLOCKS
PROGRAM
COUNTER
PSW
PSEN
ALE/PROG
EA / VPP
TIMING
AND
CONTROL
INSTRUCTION
REGISTER
DPTR
RST
PORT 1
LATCH
PORT 3
LATCH
PORT 1 DRIVERS
PORT 3 DRIVERS
OSC
P1.0 - P1.7
P3.0 - P3.7
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0811E–MICRO–9/08
4. Pin Description
4.1
VCC
Supply voltage.
4.2
GND
Ground.
4.3
Port 0
Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pin can sink eight TTL
inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance inputs.
Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses
to external program and data memory. In this mode, P0 has internal pullups.
Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pullups are required during program verification.
4.4
Port 1
Port 1 is an 8-bit bi-directional I/O port with internal pullups. The Port 1 output buffers can
sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low
will source current (IIL) because of the internal pullups.
In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input
(P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in the following table.
Port Pin
Alternate Functions
P1.0
T2 (external count input to Timer/Counter 2), clock-out
P1.1
T2EX (Timer/Counter 2 capture/reload trigger and direction control)
Port 1 also receives the low-order address bytes during Flash programming and verification.
4.5
Port 2
Port 2 is an 8-bit bi-directional I/O port with internal pullups. The Port 2 output buffers can
sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low
will source current (IIL) because of the internal pullups.
Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @ DPTR). In this
application, Port 2 uses strong internal pullups when emitting 1s. During accesses to external
data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special
Function Register.
Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.
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AT89LV55
4.6
Port 3
Port 3 is an 8-bit bi-directional I/O port with internal pullups. The Port 3 output buffers can
sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low
will source current (IIL) because of the pullups.
Port 3 also serves the functions of various special features of the AT89LV55, as shown in the
following table.
Port Pin
Alternate Functions
P3.0
RXD (serial input port)
P3.1
TXD (serial output port)
P3.2
INT0 (external interrupt 0)
P3.3
INT1 (external interrupt 1)
P3.4
T0 (timer 0 external input)
P3.5
T1 (timer 1 external input)
P3.6
WR (external data memory write strobe)
P3.7
RD (external data memory read strobe)
Port 3 also receives the highest-order address bit and some control signals for Flash programming and verification.
4.7
RST
Reset input. A high on this pin for two machine cycles while the oscillator is running resets the
device.
4.8
ALE/PROG
Address Latch Enable is an output pulse for latching the low byte of the address during
accesses to external memory. This pin is also the program pulse input (PROG) during Flash
programming.
In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be
used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory.
If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set,
ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high.
Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.
4.9
PSEN
Program Store Enable is the read strobe to external program memory.
When the AT89LV55 is executing code from external program memory, PSEN is activated twice
each machine cycle, except that two PSEN activations are skipped during each access to external data memory.
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0811E–MICRO–9/08
4.10
EA/VPP
External Access Enable. EA must be strapped to GND in order to enable the device to fetch
code from external program memory locations starting at 0000H up to FFFFH. Note, however,
that if lock bit 1 is programmed, EA will be internally latched on reset.
EA should be strapped to VCC for internal program executions.
This pin also receives the 12-volt programming enable voltage (V PP ) during 12-volt Flash
programming.
4.11
XTAL1
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
4.12
XTAL2
Output from the inverting oscillator amplifier.
5. Special Function Registers
A map of the on-chip memory area called the Special Function Register (SFR) space is shown in
Table 5-1.
Table 5-1.
AT89LV55 SFR Map and Reset Values
0F8H
0F0H
0FFH
B
00000000
0F7H
0E8H
0E0H
0EFH
ACC
00000000
0E7H
0D8H
0DFH
0D0H
PSW
00000000
0C8H
T2CON
00000000
0D7H
T2MOD
XXXXXX00
RCAP2L
00000000
RCAP2H
00000000
TL2
00000000
TH2
00000000
0CFH
0C0H
6
0C7H
0B8H
IP
XX000000
0BFH
0B0H
P3
11111111
0B7H
0A8H
IE
0X000000
0AFH
0A0H
P2
11111111
0A7H
98H
SCON
00000000
90H
P1
11111111
88H
TCON
00000000
TMOD
00000000
TL0
00000000
TL1
00000000
80H
P0
11111111
SP
00000111
DPL
00000000
DPH
00000000
SBUF
XXXXXXXX
9FH
97H
TH0
00000000
TH1
00000000
8FH
PCON
0XXX0000
87H
AT89LV55
0811E–MICRO–9/08
AT89LV55
Note that not all of the addresses are occupied, and unoccupied addresses may not be implemented on the chip. Read accesses to these addresses will in general return random data, and
write accesses will have an indeterminate effect.
User software should not write 1s to these unlisted locations, since they may be used in future
products to invoke new features. In that case, the reset or inactive values of the new bits will
always be 0.
Timer 2 Registers: Control and status bits are contained in registers T2CON (shown in Table 52) and T2MOD (shown in Table 8-2) for Timer 2. The register pair (RCAP2H, RCAP2L) are the
Capture/Reload registers for Timer 2 in 16-bit capture mode or 16-bit auto-reload mode.
Interrupt Registers: The individual interrupt enable bits are in the IE register. Two priorities can
be set for each of the six interrupt sources in the IP register.
Table 5-2.
T2CON – Timer/Counter 2 Control Register
T2CON Address = 0C8H
Reset Value = 0000 0000B
Bit Addressable
TF2
EXF2
RCLK
TCLK
EXEN2
TR2
C/T2
CP/RL2
7
6
5
4
3
2
1
0
Bit
Symbol
Function
TF2
Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set when either
RCLK = 1 or TCLK = 1.
EXF2
Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and EXEN2 = 1.
When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2 interrupt routine. EXF2 must
be cleared by software. EXF2 does not cause an interrupt in up/down counter mode (DCEN = 1).
RCLK
Receive clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock in serial port
Modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock.
TCLK
Transmit clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock in serial
port Modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock.
EXEN2
Timer 2 external enable. When set, allows a capture or reload to occur as a result of a negative transition on T2EX if
Timer 2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to ignore events at T2EX.
TR2
Start/Stop control for Timer 2. TR2 = 1 starts the timer.
C/T2
Timer or counter select for Timer 2. C/T2 = 0 for timer function. C/T2 = 1 for external event counter (falling edge
triggered).
CP/RL2
Capture/Reload select. CP/RL2 = 1 causes captures to occur on negative transitions at T2EX if EXEN2 = 1. CP/RL2 =
0 causes automatic reloads to occur when Timer 2 overflows or negative transitions occur at T2EX when EXEN2 = 1.
When either RCLK or TCLK = 1, this bit is ignored and the timer is forced to auto-reload on Timer 2 overflow.
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0811E–MICRO–9/08
6. Data Memory
The AT89LV55 implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a parallel
address space to the Special Function Registers. That means the upper 128 bytes have the
same addresses as the SFR space but are physically separate from SFR space.
When an instruction accesses an internal location above address 7FH, the address mode used
in the instruction specifies whether the CPU accesses the upper 128 bytes of RAM or the SFR
space. Instructions that use direct addressing access SFR space.
For example, the following direct addressing instruction accesses the SFR at location 0A0H
(which is P2).
MOV 0A0H, #data
Instructions that use indirect addressing access the upper 128 bytes of RAM. For example, the
following indirect addressing instruction, where R0 contains 0A0H, accesses the data byte at
address 0A0H, rather than P2 (whose address is 0A0H).
MOV @R0, #data
Note that stack operations are examples of indirect addressing, so the upper 128 bytes of data
RAM are available as stack space.
7. Timer 0 and 1
Timer 0 and Timer 1 in the AT89LV55 operate the same way as Timer 0 and Timer 1 in the
AT89C51. For further information on the timers’ operation, please click on the document link
below:
http://www.atmel.com/dyn/resources/prod_documents/DOC4316.PDF
8. Timer 2
Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an event counter. The
type of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 5-2). Timer 2 has
three operating modes: capture, auto-reload (up or down counting), and baud rate generator.
The modes are selected by bits in T2CON, as shown in Table 8-1.
Timer 2 consists of two 8-bit registers, TH2 and TL2. In the Timer function, the TL2 register is
incremented every machine cycle. Since a machine cycle consists of 12 oscillator periods, the
count rate is 1/12 of the oscillator frequency.
In the Counter function, the register is incremented in response to a 1-to-0 transition at its corresponding external input pin, T2. In this function, the external input is sampled during S5P2 of
every machine cycle. When the samples show a high in one cycle and a low in the next cycle,
the count is incremented. The new count value appears in the register during S3P1 of the cycle
following the one in which the transition was detected. Since two machine cycles (24 oscillator
periods) are required to recognize a 1-to-0 transition, the maximum count rate is 1/24 of the
oscillator frequency. To ensure that a given level is sampled at least once before it changes, the
level should be held for at least one full machine cycle.
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0811E–MICRO–9/08
AT89LV55
.
Table 8-1.
8.1
Timer 2 Operating Modes
RCLK + TCLK
CP/RL2
TR2
MODE
0
0
1
16-bit Auto-reload
0
1
1
16-bit Capture
1
X
1
Baud Rate Generator
X
X
0
(Off)
Capture Mode
In the capture mode, two options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 is
a 16-bit timer or counter which upon overflow sets bit TF2 in T2CON. This bit can then be used
to generate an interrupt. If EXEN2 = 1, Timer 2 performs the same operation, but a 1-to-0 transition at external input T2EX also causes the current value in TH2 and TL2 to be captured into
RCAP2H and RCAP2L, respectively. In addition, the transition at T2EX causes bit EXF2 in
T2CON to be set. The EXF2 bit, like TF2, can generate an interrupt. The capture mode is illustrated in Figure 8-1.
Figure 8-1.
8.2
Timer 2 in Capture Mode
Auto-reload (Up or Down Counter)
Timer 2 can be programmed to count up or down when configured in its 16-bit auto-reload
mode. This feature is invoked by the DCEN (Down Counter Enable) bit located in the SFR
T2MOD (see Table 8-2). Upon reset, the DCEN bit is set to 0 so that timer 2 will default to count
up. When DCEN is set, Timer 2 can count up or down, depending on the value of the T2EX pin.
Figure 8-2 shows Timer 2 automatically counting up when DCEN = 0. In this mode, two options
are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to 0FFFFH and then sets
the TF2 bit upon overflow. The overflow also causes the timer registers to be reloaded with the
16-bit value in RCAP2H and RCAP2L. The values in RCAP2H and RCAP2L are preset by software. If EXEN2 = 1, a 16-bit reload can be triggered either by an overflow or by a 1-to-0
transition at external input T2EX. This transition also sets the EXF2 bit. Both the TF2 and EXF2
bits can generate an interrupt if enabled.
Setting the DCEN bit enables Timer 2 to count up or down, as shown in Figure 8-3. In this mode,
the T2EX pin controls the direction of the count. A logic 1 at T2EX makes Timer 2 count up. The
timer will overflow at 0FFFFH and set the TF2 bit. This overflow also causes the 16-bit value in
RCAP2H and RCAP2L to be reloaded into the timer registers, TH2 and TL2, respectively.
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0811E–MICRO–9/08
A logic 0 at T2EX makes Timer 2 count down. The timer underflows when TH2 and TL2 equal
the values stored in RCAP2H and RCAP2L. The underflow sets the TF2 bit and causes 0FFFFH
to be reloaded into the timer registers.
The EXF2 bit toggles whenever Timer 2 overflows or underflows and can be used as a 17th bit
of resolution. In this operating mode, EXF2 does not flag an interrupt.
Figure 8-2.
Timer 2 Auto Reload Mode (DCEN = 0)
Table 8-2.
T2MOD—Timer 2 Mode Control Register
T2MOD Address = 0C9H
Reset Value = XXXX XX00B
Not Bit Addressable
Bit
–
–
–
–
–
–
T20E
DCEN
7
6
5
4
3
2
1
0
Symbol
Function
–
Not implemented, reserved for future use.
T20E
Timer 2 Output Enable bit.
DCEN
When set, this bit allows Timer 2 to be configured as an up/down counter.
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0811E–MICRO–9/08
AT89LV55
Figure 8-3.
Timer 2 Auto Reload Mode (DCEN = 1)
Figure 8-4.
Timer 2 in Baud Rate Generator Mode
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0811E–MICRO–9/08
9. Baud Rate Generator
Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON (Table
5-2). Note that the baud rates for transmit and receive can be different if Timer 2 is used for the
receiver or transmitter and Timer 1 is used for the other function. Setting RCLK and/or TCLK
puts Timer 2 into its baud rate generator mode, as shown in Figure 8-4.
The baud rate generator mode is similar to the auto-reload mode, in that a rollover in TH2
causes the Timer 2 registers to be reloaded with the 16-bit value in registers RCAP2H and
RCAP2L, which are preset by software.
The baud rates in Modes 1 and 3 are determined by Timer 2’s overflow rate according to the following equation.
Timer 2 Overflow Rate
Modes 1 and 3 Baud Rates = -----------------------------------------------------------16
The Timer can be configured for either timer or counter operation. In most applications, it is configured for timer operation (CP/T2 = 0). The timer operation is different for Timer 2 when it is
used as a baud rate generator. Normally, as a timer, it increments every machine cycle (at 1/12
the oscillator frequency). As a baud rate generator, however, it increments every state time (at
1/2 the oscillator frequency). The baud rate formula is given below.
Oscillator Frequency
Modes
1 and 3- = ----------------------------------------------------------------------------------------------------------------------------------Baud Rate
32 × [ 65536 – ( RCAP2H,RCAP2L ) ]
where (RCAP2H, RCAP2L) is the content of RCAP2H and RCAP2L taken as a 16-bit unsigned
integer.
Timer 2 as a baud rate generator is shown in Figure 8-4. This figure is valid only if RCLK or
TCLK = 1 in T2CON. Note that a rollover in TH2 does not set TF2 and will not generate an interrupt. Note too, that if EXEN2 is set, a l-to-0 transition in T2EX will set EXF2 but will not cause a
reload from (RCAP2H, RCAP2L) to (TH2, TL2). Thus when Timer 2 is in use as a baud rate generator, T2EX can be used as an extra external interrupt.
Note that when Timer 2 is running (TR2 = 1) as a timer in the baud rate generator mode, TH2 or
TL2 should not be read from or written to. Under these conditions, the Timer is incremented
every state time, and the results of a read or write may not be accurate. The RCAP2 registers
may be read but should not be written to, because a write might overlap a reload and cause
write and/or reload errors. The timer should be turned off (clear TR2) before accessing the Timer
2 or RCAP2 registers.
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0811E–MICRO–9/08
AT89LV55
Figure 9-1.
Timer 2 in Clock-out Mode
10. Programmable Clock Out
A 50% duty cycle clock can be programmed to come out on P1.0, as shown in Figure 9-1. This
pin, besides being a regular I/O pin, has two alternate functions. It can be programmed to input
the external clock for Timer/Counter 2 or to output a 50% duty cycle clock ranging from 61 Hz to
3 MHz at a 12 MHz operating frequency.
To configure the Timer/Counter 2 as a clock generator, bit C/T2 (T2CON.1) must be cleared and
bit T2OE (T2MOD.1) must be set. Bit TR2 (T2CON.2) starts and stops the timer.
The clock-out frequency depends on the oscillator frequency and the reload value of Timer 2
capture registers (RCAP2H, TCAP2L), as shown in the following equation:
Oscillator Frequency
Clock-Out Frequency = -----------------------------------------------------------------------------------------4 × [ 65536 – (RCAP2H,RCAP2L) ]
In the clock-out mode, Timer 2 roll-overs will not generate an interrupt. This behavior is similar to
when Timer 2 is used as a baud-rate generator. It is possible to use Timer 2 as a baud-rate generator and a clock generator simultaneously. Note, however, that the baud-rate and clock-out
frequencies cannot be determined independently from one another since they both use
RCAP2H and RCAP2L.
11. UART
The UART in the AT89LV55 operates the same way as the UART in the AT89C51. For further
information on the UART operation, please click on the document link below:
http://www.atmel.com/dyn/resources/prod_documents/DOC4316.PDF
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0811E–MICRO–9/08
12. Interrupts
The AT89LV55 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three
timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all shown
in Figure 12-1.
Each of these interrupt sources can be individually enabled or disabled by setting or clearing a
bit in Special Function Register IE. IE also contains a global disable bit, EA, which disables all
interrupts at once.
Note that Table 12-1 shows that bit position IE.6 is unimplemented. In the AT89C51 and
AT89LV51, bit position IE.5 is also unimplemented. User software should not write 1s to these
bit positions, since they may be used in future AT89 products.
Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON. Neither of these flags is cleared by hardware when the service routine is vectored to. In fact, the
service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt,
and that bit will have to be cleared in software.
The Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the cycle in which the timers
overflow. The values are then polled by the circuitry in the next cycle. However, the Timer 2 flag,
TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows. For further information, see the Microcontroller Data Book, section titled “Interrupts.”
Table 12-1.
Interrupt Enable (IE) Register
(MSB)
(LSB)
EA
–
ET2
ES
ET1
EX1
ET0
EX0
Enable Bit = 1 enables the interrupt.
Enable Bit = 0 disables the interrupt.
Symbol
Position
Function
EA
IE.7
Disables all interrupts. If EA = 0, no interrupt is acknowledged. If EA = 1, each
interrupt source is individually enabled or disabled by setting or clearing its
enable bit.
–
IE.6
Reserved.
ET2
IE.5
Timer 2 interrupt enable bit.
ES
IE.4
Serial Port interrupt enable bit.
ET1
IE.3
Timer 1 interrupt enable bit.
EX1
IE.2
External interrupt 1 enable bit.
ET0
IE.1
Timer 0 interrupt enable bit.
EX0
IE.0
External interrupt 0 enable bit.
User software should never write 1s to unimplemented bits, because they may be used in future AT89 products.
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AT89LV55
Figure 12-1. Interrupt Sources
13. Oscillator Characteristics
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be
configured for use as an on-chip oscillator, as shown in Figure 15-1. Either a quartz crystal or
ceramic resonator may be used. To drive the device from an external clock source, XTAL2
should be left unconnected while XTAL1 is driven, as shown in Figure 15-2. There are no
requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low
time specifications must be observed.
14. Idle Mode
In idle mode, the CPU puts itself to sleep while all the on-chip peripherals remain active. The
mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled
interrupt or by a hardware reset.
Note that when idle mode is terminated by a hardware reset, the device normally resumes program execution from where it left off, up to two machine cycles before the internal reset
algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but
access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a
port pin when idle mode is terminated by a reset, the instruction following the one that invokes
idle mode should not write to a port pin or to external memory.
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15. Power-down Mode
In the power-down mode, the oscillator is stopped, and the instruction that invokes power-down
is the last instruction executed. The on-chip RAM and Special Function Registers retain their
values until the power-down mode is terminated. The only exit from power-down is a hardware
reset. Reset redefines the SFRs but does not change the on-chip RAM. The reset should not be
activated before VCC is restored to its normal operating level and must be held active long
enough to allow the oscillator to restart and stabilize.
Figure 15-1. Oscillator Connections
Note:
C1, C2 = 30 pF ± 10 pF for Crystals
= 40 pF ± 10 pF for Ceramic Resonators
Figure 15-2. External Clock Drive Configuration
Table 15-1.
Status of External Pins During Idle and Power-down Modes
Mode
Program Memory
ALE
PSEN
PORT0
PORT1
PORT2
PORT3
Idle
Internal
1
1
Data
Data
Data
Data
Idle
External
1
1
Float
Data
Address
Data
Power-down
Internal
0
0
Data
Data
Data
Data
Power-down
External
0
0
Float
Data
Data
Data
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AT89LV55
16. Program Memory Lock Bits
The AT89LV55 has three lock bits that can be left unprogrammed (U) or can be programmed (P)
to obtain the additional features listed in Table 16-1:
Table 16-1.
Lock Bit Protection Modes
Program Lock Bits
1
LB1
LB2
LB3
Protection Type
U
U
U
No program lock features.
2
P
U
U
MOVC instructions executed from external program memory are
disabled from fetching code bytes from internal memory, EA is
sampled and latched on reset, and further programming of the
Flash memory is disabled.
3
P
P
U
Same as mode 2, but verify is also disabled.
4
P
P
P
Same as mode 3, but external execution is also disabled.
When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched during reset.
If the device is powered up without a reset, the latch initializes to a random value and holds that
value until reset is activated. The latched value of EA must agree with the current logic level at
that pin in order for the device to function properly.
The AT89LV55 code memory array is programmed byte-by-byte. To program any non-blank
byte in the on-chip Flash Memory, the entire memory must be erased using the Chip
Erase Mode.
17. Programming the Flash
The AT89LV55 is normally shipped with the on-chip Flash memory array in the erased state
(that is, contents = FFH) and ready to be programmed.
Programming Algorithm: Before programming the AT89LV55, the address, data and control
signals should be set up according to Table 18-1, “Flash Programming Modes,” on page 19 and
Figure 18-1. To program the AT89LV55, take the following steps:
1. Input the desired memory location on the address lines.
2. Input the appropriate data byte on the data lines.
3. Activate the correct combination of control signals.
4. Raise EA/VPP to 12V
5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits. The bytewrite cycle is self-timed and typically takes no more than 1.5 ms. Repeat steps 1
through 5, changing the address and data for the entire array or until the end of the
object file is reached.
Data Polling: The AT89LV55 features Data Polling to indicate the end of a write cycle. During a
write cycle, an attempted read of the last byte written will result in the complement of the written
data on PO.7. Once the write cycle has been completed, true data is valid on all outputs, and the
next cycle may begin. Data Polling may begin any time after a write cycle has been initiated.
Ready/Busy: The progress of byte programming can also be monitored by the RDY/BUSY output signal. P3.4 is pulled low after ALE goes high during programming to indicate BUSY. P3.4 is
pulled high again when programming is done to indicate READY.
17
0811E–MICRO–9/08
Program Verify: If lock bits LB1 and LB2 have not been programmed, the programmed code
data can be read back via the address and data lines for verification. The lock bits cannot be verified directly. Verification of the lock bits is achieved by observing that their features are enabled.
Figure 17-1. Programming the Flash Memory
+5V
AT89LV55
A0 - A7
ADDR.
0000H/4FFFH
A8 - A13
A14*
SEE FLASH
PROGRAMMING
MODES TABLE
P1.0 - P1.7 VCC
P2.0 - P2.5
P3.0
P2.6
P0
PGM
DATA
ALE
PROG
XTAL2
EA
VI H/VPP
XTAL1
RST
P2.7
P3.6
P3.7
3-12 MHz
GND
VI H
PSEN
*Programming address line A14 (P3.0) is not the same
as the external memory address line A14 (P2.6)
Chip Erase: The entire Flash array is erased electrically by using the proper combination of
control signals and by holding ALE/PROG low for 10 ms. The code array is written with all 1s.
The chip erase operation must be executed before the code memory can be reprogrammed.
Reading the Signature Bytes: The signature bytes are read by the same procedure as a normal verification of locations 030H, and 031H, except that P3.6 and P3.7 must be pulled to a logic
low. The values returned are as follows:
(030H) = 1EH indicates manufactured by Atmel
(031H) = 65H indicates 89LV55
(032H) = FFH indicates 12V programming
18
AT89LV55
0811E–MICRO–9/08
AT89LV55
18. Programming Interface
Every code byte in the Flash array can be written, and the entire array can be erased, by using
the appropriate combination of control signals. The write operation cycle is self-timed and once
initiated, will automatically time itself to completion.
All major programming vendors offer worldwide support for the Atmel microcontroller series.
Please contact your local programming vendor for the appropriate software revision.
Figure 18-1. Verifying the Flash Memory
+5V
AT89LV55
ADDR.
0000H/4FFFH
A0 - A7
A8 - A13
A14*
SEE FLASH
PROGRAMMING
MODES TABLE
P1.0 - P1.7
VCC
P2.0 - P2.5
P0
P3.0
P2.6
P2.7
PGM DATA
(USE 10K
PULLUPS)
ALE
P3.6
VI H
P3.7
XTAL2
EA
XTAL1
RST
3-12 MHz
GND
Table 18-1.
PSEN
Flash Programming Modes
Mode
Write Code Data
Read Code Data
Write Lock
Bit-1
Bit-2
Bit-3
Chip Erase
Read Signature Byte
Note:
VI H
RST
PSEN
H
L
H
L
H
ALE/PROG
EA/VPP
P2.6
P2.7
P3.6
P3.7
12V
L
H
H
H
H
L
L
H
H
L
12V
H
H
H
H
H
L
12V
H
H
L
L
H
L
12V
H
L
H
L
H
L
12V
H
L
L
L
H
L
H
L
L
L
L
H
H
1. Chip Erase requires a 10 ms PROG pulse.
19
0811E–MICRO–9/08
19. Flash Programming and Verification Characteristics
TA = 0°C to 70°C, VCC = 5.0V ± 10%
Symbol
Parameter
Min
Max
Units
VPP
Programming Enable Voltage
11.5
12.5
V
IPP
Programming Enable Current
1.0
mA
1/tCLCL
Oscillator Frequency
12
MHz
tAVGL
Address Setup to PROG Low
48tCLCL
tGHAX
Address Hold After PROG
48tCLCL
tDVGL
Data Setup to PROG Low
48tCLCL
tGHDX
Data Hold After PROG
48tCLCL
tEHSH
P2.7 (ENABLE) High to VPP
48tCLCL
tSHGL
VPP Setup to PROG Low
10
µs
tGHSL
VPP Hold After PROG
10
µs
tGLGH
PROG Width
1
tAVQV
Address to Data Valid
48tCLCL
tELQV
ENABLE Low to Data Valid
48tCLCL
tEHQZ
Data Float After ENABLE
tGHBL
PROG High to BUSY Low
1.0
µs
tWC
Byte Write Cycle Time
2.0
ms
3
0
110
µs
48tCLCL
20. Flash Programming and Verification Waveforms (VPP = 12V)
20
AT89LV55
0811E–MICRO–9/08
AT89LV55
21. Absolute Maximum Ratings*
Operating Temperature ..............................................-55°C to +125°C
*NOTICE:
Storage Temperature ..................................................-65°C to +150°C
Voltage on Any Pin
with Respect to Ground ................................................. -1.0V to +7.0V
Maximum Operating Voltage .........................................................6.6V
DC Output Current...................................................................15.0 mA
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at these or any other conditions
beyond those indicated in the operational sections of
this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may
affect device reliability.
22. DC Characteristics
The values shown in this table are valid for TA = -40°C to 85°C and VCC = 2.7V to 6.0V, unless otherwise noted.
Symbol
Parameter
Condition
Min
Max
Units
VIL
Input Low Voltage
(Except EA)
-0.5
0.2 VCC - 0.1
V
VIL1
Input Low Voltage (EA)
VIH
Input High Voltage
VIH1
Input High Voltage
VOL
VOL1
Output Low Voltage
-0.5
0.2 VCC - 0.3
V
0.2 VCC + 0.9
VCC + 0.5
V
0.7 VCC
VCC + 0.5
V
IOL = 1.6 mA
0.45
V
IOL = 3.2 mA
0.45
V
(Except XTAL1, RST)
(XTAL1, RST)
(1)
(Ports 1, 2, 3)
Output Low Voltage (1)
(Port 0, ALE, PSEN)
IOH = -60 μA, VCC = 5V ± 10%
VOH
Output High Voltage
(Ports 1, 2, 3, ALE, PSEN)
2.4
V
IOH = -25 μA
0.75 VCC
V
IOH = -10 μA
0.9 VCC
V
IOH = -800 μA, VCC = 5V ± 10%
VOH1
Output High Voltage
(Port 0 in External Bus Mode)
2.4
V
IOH = -300 μA
0.75 VCC
V
IOH = -80 μA
0.9 VCC
V
IIL
Logical 0 Input Current
(Ports 1, 2, 3)
VIN = 0.45V
-50
μA
ITL
Logical 1 to 0 Transition Current
(Ports 1, 2, 3)
VIN = 2V
-650
μA
ILI
Input Leakage Current
(Port 0, EA)
0.45 < VIN < VCC
±10
μA
RRST
Reset Pulldown Resistor
300
kΩ
CIO
Pin Capacitance
Power Supply Current
ICC
Power-down Mode (1)
Notes:
50
Test Freq. = 1 MHz, TA = 25°C
10
pF
Active Mode, 12 MHz
25
mA
Idle Mode, 12 MHz
6.5
mA
VCC = 6V
100
μA
VCC = 3V
40
μA
1. Under steady state (non-transient) conditions, IOL must be externally limited as follows:
Maximum IOL per port pin: 10 mA
Maximum IOL per 8-bit port:
Port 0: 26 mA, Ports 1, 2, 3: 15 mA
Maximum total IOL for all output pins: 71 mA
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater
than the listed test conditions.
2. Minimum VCC for Power-down is 2V.
21
0811E–MICRO–9/08
23. AC Characteristics
Under operating conditions, load capacitance for Port 0, ALE/PROG, and PSEN = 100 pF; load capacitance for all other
outputs = 80 pF.
23.1
External Program and Data Memory Characteristics
12 MHz Oscillator
Max
Min
Max
0
12
Units
Symbol
Parameter
1/tCLCL
Oscillator Frequency
tLHLL
ALE Pulse Width
127
2tCLCL - 40
ns
tAVLL
Address Valid to ALE Low
43
tCLCL - 40
ns
tLLAX
Address Hold After ALE Low
48
tCLCL - 35
ns
tLLIV
ALE Low to Valid Instruction In
tLLPL
ALE Low to PSEN Low
43
tCLCL - 40
ns
tPLPH
PSEN Pulse Width
205
3tCLCL - 45
ns
tPLIV
PSEN Low to Valid Instruction In
tPXIX
Input Instruction Hold After PSEN
tPXIZ
Input Instruction Float After PSEN
tPXAV
PSEN to Address Valid
tAVIV
Address to Valid Instruction In
312
5tCLCL - 105
ns
tPLAZ
PSEN Low to Address Float
10
10
ns
tRLRH
RD Pulse Width
400
6tCLCL - 100
ns
tWLWH
WR Pulse Width
400
6tCLCL - 100
ns
tRLDV
RD Low to Valid Data In
tRHDX
Data Hold After RD
tRHDZ
Data Float After RD
97
2tCLCL - 70
ns
tLLDV
ALE Low to Valid Data In
517
8tCLCL - 150
ns
tAVDV
Address to Valid Data In
585
9tCLCL - 165
ns
tLLWL
ALE Low to RD or WR Low
200
3tCLCL + 50
ns
tAVWL
Address to RD or WR Low
203
4tCLCL - 130
ns
tQVWX
Data Valid to WR Transition
23
tCLCL - 60
ns
tQVWH
Data Valid to WR High
433
7tCLCL - 150
ns
tWHQX
Data Hold After WR
33
tCLCL - 50
ns
tRLAZ
RD Low to Address Float
tWHLH
RD or WR High to ALE High
22
Min
Variable Oscillator
233
4tCLCL - 100
145
0
3tCLCL - 105
0
59
75
tCLCL - 8
0
5tCLCL - 165
3tCLCL - 50
0
43
123
tCLCL - 40
ns
ns
ns
0
300
ns
ns
tCLCL - 25
252
MHz
ns
ns
0
ns
tCLCL + 40
ns
AT89LV55
0811E–MICRO–9/08
AT89LV55
24. External Program Memory Read Cycle
25. External Data Memory Read Cycle
23
0811E–MICRO–9/08
26. External Data Memory Write Cycle
27. External Clock Drive Waveforms
24
AT89LV55
0811E–MICRO–9/08
AT89LV55
28. External Clock Drive
Symbol
Parameter
1/tCLCL
Oscillator Frequency
tCLCL
Clock Period
tCHCX
Min
Max
Units
0
12
MHz
83.3
ns
High Time
20
ns
tCLCX
Low Time
20
ns
tCLCH
Rise Time
20
ns
tCHCL
Fall Time
20
ns
29. Serial Port Timing: Shift Register Mode Test Conditions
The values in this table are valid for VCC = 5.0V ± 20% and Load Capacitance = 80 pF.
12 MHz Osc
Variable Oscillator
Max
Symbol
Parameter
Min
tXLXL
Serial Port Clock Cycle Time
1.0
12tCLCL
ns
tQVXH
Output Data Setup to Clock Rising
Edge
700
10tCLCL - 133
ns
tXHQX
Output Data Hold After Clock
Rising Edge
50
2tCLCL - 117
ns
tXHDX
Input Data Hold After Clock Rising
Edge
0
0
ns
tXHDV
Clock Rising Edge to Input Data
Valid
700
Min
Units
Max
10tCLCL - 133
ns
25
0811E–MICRO–9/08
30. Shift Register Mode Timing Waveforms
31. AC Testing Input/Output Waveforms (1)
Note:
1. AC Inputs during testing are driven at 2.4V for a logic “1” and 0.45V for a logic “0”. Timing measurements are made at 2.0V
for a logic “1” and 0.8V for a logic “0”.
32. Float Waveforms (1)
Note:
26
1. For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage occurs. A port pin begins to
float when a 100 mV change from the loaded VOH/VOL level occurs.
AT89LV55
0811E–MICRO–9/08
AT89LV55
Notes:
1. XTAL1 tied to GND for ICC (power-down)
2. Lock bits programmed
27
0811E–MICRO–9/08
33. Ordering Information
Speed
(MHz)
12
Power
Supply
2.7V - 6.0V
Ordering Code
Package
Operation Range
AT89LV55-12AC
AT89LV55-12JC
AT89LV55-12PC
44A
44J
40P6
Commercial
(0° C to 70° C)
AT89LV55-12AI
AT89LV55-12JI
AT89LV55-12PI
44A
44J
40P6
Industrial
(-40° C to 85° C)
Package Type
44A
44-lead, Thin Plastic Gull Wing Quad Flatpack (TQFP)
44J
44-lead, Plastic J-Leaded Chip Carrier (PLCC)
40P6
40-lead, 0.600" Wide, Plastic Dual Inline Package (PDIP)
28
AT89LV55
0811E–MICRO–9/08
AT89LV55
34. Package Information
34.1
44A – TQFP
PIN 1
B
PIN 1 IDENTIFIER
E1
e
E
D1
D
C
0˚~7˚
A1
A2
A
L
COMMON DIMENSIONS
(Unit of Measure = mm)
Notes:
1. This package conforms to JEDEC reference MS-026, Variation ACB.
2. Dimensions D1 and E1 do not include mold protrusion. Allowable
protrusion is 0.25 mm per side. Dimensions D1 and E1 are maximum
plastic body size dimensions including mold mismatch.
3. Lead coplanarity is 0.10 mm maximum.
SYMBOL
MIN
NOM
MAX
A
–
–
1.20
A1
0.05
–
0.15
A2
0.95
1.00
1.05
D
11.75
12.00
12.25
D1
9.90
10.00
10.10
E
11.75
12.00
12.25
E1
9.90
10.00
10.10
B
0.30
–
0.45
C
0.09
–
0.20
L
0.45
–
0.75
e
NOTE
Note 2
Note 2
0.80 TYP
10/5/2001
R
2325 Orchard Parkway
San Jose, CA 95131
TITLE
44A, 44-lead, 10 x 10 mm Body Size, 1.0 mm Body Thickness,
0.8 mm Lead Pitch, Thin Profile Plastic Quad Flat Package (TQFP)
DRAWING NO.
REV.
44A
B
29
0811E–MICRO–9/08
34.2
44J – PLCC
1.14(0.045) X 45˚
PIN NO. 1
1.14(0.045) X 45˚
0.318(0.0125)
0.191(0.0075)
IDENTIFIER
E1
D2/E2
B1
E
B
e
A2
D1
A1
D
A
0.51(0.020)MAX
45˚ MAX (3X)
COMMON DIMENSIONS
(Unit of Measure = mm)
Notes:
1. This package conforms to JEDEC reference MS-018, Variation AC.
2. Dimensions D1 and E1 do not include mold protrusion.
Allowable protrusion is .010"(0.254 mm) per side. Dimension D1
and E1 include mold mismatch and are measured at the extreme
material condition at the upper or lower parting line.
3. Lead coplanarity is 0.004" (0.102 mm) maximum.
SYMBOL
MIN
NOM
MAX
A
4.191
–
4.572
A1
2.286
–
3.048
A2
0.508
–
–
D
17.399
–
17.653
D1
16.510
–
16.662
E
17.399
–
17.653
E1
16.510
–
16.662
D2/E2
14.986
–
16.002
B
0.660
–
0.813
B1
0.330
–
0.533
e
NOTE
Note 2
Note 2
1.270 TYP
10/04/01
R
30
2325 Orchard Parkway
San Jose, CA 95131
TITLE
44J, 44-lead, Plastic J-leaded Chip Carrier (PLCC)
DRAWING NO.
REV.
44J
B
AT89LV55
0811E–MICRO–9/08
AT89LV55
34.3
40P6 – PDIP
D
PIN
1
E1
A
SEATING PLANE
A1
L
B
B1
e
E
0º ~ 15º
C
COMMON DIMENSIONS
(Unit of Measure = mm)
REF
MIN
NOM
MAX
A
–
–
4.826
A1
0.381
–
–
D
52.070
–
52.578
E
15.240
–
15.875
E1
13.462
–
13.970
B
0.356
–
0.559
B1
1.041
–
1.651
L
3.048
–
3.556
C
0.203
–
0.381
eB
15.494
–
17.526
SYMBOL
eB
Notes:
1. This package conforms to JEDEC reference MS-011, Variation AC.
2. Dimensions D and E1 do not include mold Flash or Protrusion.
Mold Flash or Protrusion shall not exceed 0.25 mm (0.010").
e
NOTE
Note 2
Note 2
2.540 TYP
09/28/01
R
2325 Orchard Parkway
San Jose, CA 95131
TITLE
40P6, 40-lead (0.600"/15.24 mm Wide) Plastic Dual
Inline Package (PDIP)
DRAWING NO.
40P6
REV.
B
31
0811E–MICRO–9/08
Headquarters
International
Atmel Corporation
2325 Orchard Parkway
San Jose, CA 95131
USA
Tel: 1(408) 441-0311
Fax: 1(408) 487-2600
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0811E–MICRO–9/08
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