MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander General Description The MAX7300 compact, serial-interfaced, I/O expansion peripheral provides microprocessors with up to 28 ports. Each port is individually user configurable to either a logic input or logic output. Each port can be configured as either a push-pull logic output capable of sinking 10mA and sourcing 4.5mA, or a Schmitt logic input with optional internal pullup. Seven ports feature configurable transition detection logic, which generates an interrupt upon change of port logic level. The MAX7300 is controlled through an I2C-compatible 2-wire serial interface, and uses four-level logic to allow 16 I2C addresses from only two select pins. The MAX7300AAX and MAX7300ATL have 28 ports and are available in 36-pin SSOP and 40-pin TQFN packages, respectively. The MAX7300AAI and MAX7300ATI have 20 ports and are available in 28-pin SSOP and TQFN packages. For an SPI-interfaced version, refer to the MAX7301 data sheet. For a pin-compatible port expander with additional 24mA constant-current LED drive capability, refer to the MAX6956 data sheet. Application ●● White Goods ●● Industrial Controllers ●● System Monitoring Pin Configurations ●● 400kbps I2C-Compatible Serial Interface ●● 2.5V to 5.5V Operation ●● -40°C to +125°C Temperature Range ●● 20 or 28 I/O Ports, Each Configurable as Push-Pull Logic Output Schmitt Logic Input Schmitt Logic Input with Internal Pullup ●● 11µA (max) Shutdown Current ●● Logic Transition Detection for Seven I/O Ports Ordering Information PART TEMP RANGE -40°C to +125°C 28 SSOP MAX7300ATI -40°C to +125°C 28 TQFN-EP* MAX7300AAX -40°C to +125°C 36 SSOP MAX7300ATL -40°C to +125°C 40 TQFN-EP* *EP = Exposed pad. Devices are also available in a lead(Pb)-free/RoHS-compliant package. Specify lead-free by adding “+” to the part number when ordering. Devices are also available in tape-and-reel packaging. Specify tape and reel by adding “T” to the part number when ordering. Typical Operating Circuit 47nF ISET 1 28 V+ GND 2 27 AD1 GND 3 26 SCL AD0 4 25 SDA P12 5 MAX7300 24 P31 P13 6 23 P30 P14 7 22 P29 P15 8 21 P28 P16 9 20 P27 P17 10 19 P26 P18 11 18 P25 P19 12 17 P24 P20 13 16 P23 P21 14 15 P22 28 SSOP Pin Configurations continued at end of data sheet. PIN-PACKAGE MAX7300AAI P4 32 P5 30 P6 28 P7 26 3V TOP VIEW 19-2413; Rev 8; 5/14 Features 39kΩ 36 V+ 3 GND 2 GND 1 ISET P8 P9 P10 35 DATA CLOCK AD1 4 AD0 33 SDA 34 SCL 31 P31 29 P30 27 P29 25 P28 24 P27 23 P26 22 P25 21 P24 MAX7300AAX 5 7 9 11 P11 P12 6 P13 8 P14 10 P15 12 P16 13 P17 14 P18 15 P19 16 P20 17 P21 18 P22 19 P23 20 I/O 4 I/O 5 I/O 6 I/O 7 I/O 8 I/O 9 I/O 10 I/O 11 I/O 12 I/O 13 I/O 14 I/O 15 I/O 16 I/O 17 I/O 18 I/O 19 I/O 20 I/O 21 I/O 22 I/O 23 I/O 24 I/O 25 I/O 26 I/O 27 I/O 28 I/O 29 I/O 30 I/O 31 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Absolute Maximum Ratings Voltage (with respect to GND) V+.............................................................................-0.3V to +6V SCL, SDA, AD0, AD1...............................................-0.3V to +6V All Other Pins...............................................-0.3V to (V+ + 0.3V) P4–P31 Current ...............................................................±30mA GND Current.....................................................................800mA Continuous Power Dissipation (TA = +70°C) 28-Pin SSOP (derate 9.1mW/°C above +70°C)...........727mW 28-Pin TQFN (derate 21.3mW/°C above +70°C).......1702mW 36-Pin SSOP (derate 11.8mW/°C above +70°C).........941mW 40-Pin TQFN (derate 26.3mW/°C above TA = +70°C).....2105mW Operating Temperature Range TMIN to TMAX)................................................ -40°C to +125°C Junction Temperature.......................................................+150°C Storage Temperature Range............................. -65°C to +150°C Lead Temperature (soldering, 10s).................................. +300°C Soldering Temperature (reflow) Lead (Pb)-free packages..............................................+260°C Packages containing lead (Pb).....................................+240°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Electrical Characteristics (Typical Operating Circuit, VV+ = 2.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER Operating Supply Voltage Shutdown Supply Current Operating Supply Current Operating Supply Current Operating Supply Current SYMBOL CONDITIONS V+ ISHDN IGPOH IGPOL IGPI MIN TYP 2.5 All digital inputs at V+ or GND TA = +25°C 5.5 MAX UNITS 5.5 V 8 TA = -40°C to +85°C 10 TMIN to TMAX 11 All ports programmed TA = +25°C as outputs high, no TA = -40°C to +85°C load, all other inputs at V+ or GND TMIN to TMAX 180 All ports programmed TA = +25°C as outputs low, no TA = -40°C to +85°C load, all other inputs at V+ or GND TMIN to TMAX 170 µA 240 260 µA 280 210 230 µA 240 All ports programmed TA = +25°C as inputs without pullup, ports, and all TA = -40°C to +85°C other inputs at V+ or TMIN to TMAX GND 110 135 140 µA 145 INPUTS AND OUTPUTS Logic High Input Voltage Port Inputs VIH Logic Low Input Voltage Port Inputs VIL Input Leakage Current IIH, IIL GPIO Input Internal Pullup to V+ IPU Hysteresis Voltage GPIO Inputs DVI www.maximintegrated.com 0.7 x V+ GPIO inputs without pullup, VPORT = V+ to GND V 0.3 x V+ V nA -100 ±1 +100 VV+ = 2.5V 12 19 30 VV+ = 5.5V 80 120 180 0.3 µA V Maxim Integrated │ 2 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Electrical Characteristics (continued) (Typical Operating Circuit, VV+ = 2.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER Output High Voltage Port Sink Current Output Short-Circuit Current SYMBOL VOH IOL IOLSC Input High-Voltage SDA, SCL, AD0, AD1 VIH Input Low-Voltage SDA, SCL, AD0, AD1 VIL Input Leakage Current SDA, SCL VOL MIN GPIO outputs, ISOURCE = 2mA, TA = -40°C to +85°C V+ 0.7 GPIO outputs, ISOURCE = 1mA, TA = TMIN to TMAX (Note 2) V+ 0.7 VPORT = 0.6V Port configured output low, shorted to V+ TYP MAX UNITS V 2 10 18 mA 2.75 11 20 mA 0.7 x V+ IIH, IIL Input Capacitance Output Low-Voltage SDA CONDITIONS V -50 0.3 x V+ V +50 nA (Note 2) 10 pF ISINK = 6mA 0.4 V MAX UNITS 400 kHz Timing Characteristics (Figure 2) (VV+ = 2.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP Serial Clock Frequency fSCL Bus Free Time Between a STOP and a START Condition tBUF 1.3 µs Hold Time (Repeated) START Condition tHD, STA 0.6 µs Repeated START Condition Setup Time tSU, STA 0.6 µs STOP Condition Setup Time tSU, STO 0.6 µs Data Hold Time tHD, DAT Data Setup Time tSU, DAT 100 ns SCL Clock Low Period tLOW 1.3 µs SCL Clock High Period tHIGH 0.7 µs (Note 3) 15 900 ns Rise Time of Both SDA and SCL Signals, Receiving tR (Notes 2, 4) 20 + 0.1Cb 300 ns Fall Time of Both SDA and SCL Signals, Receiving tF (Notes 2, 4) 20 + 0.1Cb 300 ns tF,TX (Notes 2, 5) 20 + 0.1Cb 250 ns Pulse Width of Spike Suppressed tSP (Notes 2, 6) 50 ns Capacitive Load for Each Bus Line Cb (Note 2) 400 pF Fall Time of SDA Transmitting www.maximintegrated.com 0 Maxim Integrated │ 3 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Timing Characteristics (Figure 2) (continued) (VV+ = 2.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) Note 1: All parameters tested at TA = +25°C. Specifications over temperature are guaranteed by design. Note 2: Guaranteed by design. Note 3: A master device must provide a hold time of at least 300ns for the SDA signal (referred to VIL of the SCL signal) in order to bridge the undefined region of SCL’s falling edge. Note 4:Cb = total capacitance of one bus line in pF. tR and tF measured between 0.3V+ and 0.7V+. Note 5:ISINK ≤ 6mA. Cb = total capacitance of one bus line in pF. tR and tF measured between 0.3V+ and 0.7V+. Note 6: Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns. Typical Operating Characteristics (RISET = 39kΩ, TA = +25°C, unless otherwise noted.) ALL PORTS OUTPUT (0) ALL PORTS OUTPUT (1) 0.24 0.20 0.16 0.12 0.08 VV+ = 3.3V 6 5 VV+ = 2.5V MAX7300 toc03 ALL PORTS OUTPUT (1) ALL PORTS OUTPUT (0) 4 ALL PORTS INPUT (PULLUPS DISABLED) ALL PORTS INPUT HIGH 0.04 0 VV+ = 5.5V 7 1 OPERATING SUPPLY CURRENT vs. V+ (OUTPUTS UNLOADED) SUPPLY CURRENT ( mA) 0.32 0.28 8 MAX7300 toc02 VV+ = 2.5V TO 5.5V NO LOAD SUPPLY CURRENT (A) SUPPLY CURRENT (mA) 0.36 MAX7300 toc01 0.40 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE OPERATING SUPPLY CURRENT vs. TEMPERATURE -40.0 -12.5 15.0 42.5 70.0 TEMPERATURE (°C) www.maximintegrated.com 97.5 125.0 3 -40.0 -12.5 15.0 42.5 70.0 TEMPERATURE (°C) 97.5 125.0 0.1 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 V+ (V) Maxim Integrated │ 4 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Typical Operating Characteristics (continued) (RISET = 39kΩ, TA = +25°C, unless otherwise noted.) 12 10 8 6 4 -40.0 PULLUP CURRENT (A) 15.0 42.5 70.0 97.5 4 3 -40.0 -12.5 15.0 42.5 70.0 97.5 GPI PULLUP CURRENT vs. TEMPERATURE GPO SHORT-CIRCUIT CURRENT vs. TEMPERATURE 100 VV+ = 3.3V -12.5 15.0 42.5 70.0 TEMPERATURE (°C) 125.0 GPO = 0, PORT SHORTED TO V+ 10 VV+ = 2.5V www.maximintegrated.com VV+ = 2.5V 5 TEMPERATURE (°C) 100 -40.0 VV+ = 3.3V 6 TEMPERATURE (°C) VV+ = 5.5V 10 VV+ = 5.5V 7 2 125.0 MAX7300 toc06 1000 -12.5 PORT CURRENT (mA) 2 MAX7300 toc05 14 VPORT = 1.4V 8 MAX7300 toc07 PORT SINK CURRENT (mA) 16 9 PORT SOURCE CURRENT (mA) VV+ = 2.5V TO 5.5V, VPORT = 0.6V MAX7300 toc04 18 GPO SOURCE CURRENT vs. TEMPERATURE (OUTPUT = 1) GPO SINK CURRENT vs. TEMPERATURE (OUTPUT = 0) GPO = 1, PORT SHORTED TO GND 97.5 125.0 1 -40.0 -12.5 15.0 42.5 70.0 97.5 125.0 TEMPERATURE (°C) Maxim Integrated │ 5 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Pin Description PIN NAME 28 SSOP 28 TQFN-EP 36 SSOP 40 TQFN-EP 1 26 1 36 ISET 2, 3 27, 28 2, 3 37, 38, 39 GND 4 1 4 5–24 2–21 — — — 5–32 — — — 25 22 26 FUNCTION Bias Current Setting. Connect ISET to GND through a resistor (RISET) value of 39kW to 120kW. Ground Address Input 0. Sets device slave address. Connect to either GND, V+, SCL, SDA to give four logic combinations. See Table 3. I/O Ports. P12 to P31 can be configured as push-pull outputs, — P12–P31 CMOS-logic inputs, or CMOS-logic inputs with weak pullup resistor. 1–10, 12–19, I/O Ports. P4 to P31 can be configured as push-pull outputs, P4–P31 CMOS-logic inputs, or CMOS-logic inputs with weak pullup resistor. 21–30 11, 20, 31 N.C. No Connection. Not internally connected. 40 AD0 33 32 SDA I2C-Compatible Serial-Data I/O 23 34 33 SCL I2C-Compatible Serial-Clock Input 27 24 35 34 AD1 28 25 36 35 V+ — — — — EP Detailed Description The MAX7300 general-purpose input/output (GPIO) peripheral provides up to 28 I/O ports, P4 to P31, controlled through an I2C-compatible serial interface. The ports can be configured to any combination of logic inputs and logic outputs, and default to logic inputs on power-up. Figure 1 is the MAX7300 functional diagram. Any I/O port can be configured as a push-pull output (sinking 10mA, sourcing 4.5mA), or a Schmitt-trigger logic input. Each input has an individually selectable internal pullup resistor. Additionally, transition detection allows seven ports (P24 to P30) to be monitored in any maskable combination for changes in their logic status. A detected transition is flagged through a status register bit, as well as an interrupt pin (port P31), if desired. The port configuration registers individually set the 28 ports, P4 to P31, as GPIO. A pair of bits in registers 0x09 through 0x0F sets each port’s configuration (Tables 1 and 2). The 36-pin MAX7300AAX and 40-pin MAX7300ATL have 28 ports, P4 to P31. The 28-pin MAX7300ANI, MAX7300AAI, and MAX7300ATI have only 20 ports available, P12 to P31. The eight unused ports should be configured as outputs on power-up by writing 0x55 to www.maximintegrated.com Address Input 1. Sets device slave address. Connect to either GND, V+, SCL, SDA to give four logic combinations. See Table 3. Positive Supply Voltage. Bypass V+ to GND with minimum 0.047µF capacitor. Exposed Pad (TQFN Only). EP is internally connected to GND. Connect to a large ground plane to maximize thermal performance. Not intended as an electrical connection point. registers 0x09 and 0x0A. If this is not done, the eight unused ports remain as unconnected inputs and quiescent supply current rises, although there is no damage to the part. Register Control of I/O Ports Across Multiple Drivers The MAX7300 offers 20 or 28 I/O ports, depending on package choice. Two addressing methods are available. Any single port (bit) can be written (set/cleared) at once; or, any sequence of eight ports can be written (set/cleared) in any combination at once. There are no boundaries; it is equally acceptable to write P0 to P7, P1 to P8, or P31 to P38 (P32 to P38 are nonexistent, so the instructions to these bits are ignored). Shutdown When the MAX7300 is in shutdown mode, all ports are forced to inputs, and the pullup current sources are turned off. Data in the port and control registers remain unaltered, so port configuration and output levels are restored when the MAX7300 is taken out of shutdown. The MAX7300 can still be programmed while in shutdown mode. For minimum supply current in shutdown mode, logic inputs should be at GND or V+ potential. Shutdown mode is exited by setting the S bit in the configuration register (Table 8). Maxim Integrated │ 6 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Table 1. Port Configuration Map ADDRESS CODE (HEX) REGISTER REGISTER DATA D7 D6 D5 D4 D3 D2 P5 D1 D0 Port Configuration for P7, P6, P5, P4 0x09 P7 P6 P4 Port Configuration for P11, P10, P9, P8 0x0A P11 P10 P9 P8 Port Configuration for P15, P14, P13, P12 0x0B P15 P14 P13 P12 Port Configuration for P19, P18, P17, P16 0x0C P19 P18 P17 P16 Port Configuration for P23, P22, P21, P20 0x0D P23 P22 P21 P20 Port Configuration for P27, P26, P25, P24 0x0E P27 P26 P25 P24 Port Configuration for P31, P30, P29, P28 0x0F P31 P30 P29 P28 Table 2. Port Configuration Matrix MODE PORT REGISTER (0x20–0x5F) FUNCTION PIN BEHAVIOR DO NOT USE THIS SETTING Output GPIO Output Input GPIO Input without Pullup Input GPIO Input with Pullup PORT CONFIGURATION BIT PAIR UPPER LOWER 0x09 to 0x0F 0 0 0x09 to 0x0F 0 1 Register bit = 0 Active-low logic output Register bit = 1 Active-high logic output Register bit = input logic level Schmitt logic input 0x09 to 0x0F 1 0 Schmitt logic input with pullup 0x09 to 0x0F 1 1 Serial Interface Serial Addressing The MAX7300 operates as a slave that sends and receives data through an I2C-compatible 2-wire interface. The interface uses a serial data line (SDA) and a serial clock line (SCL) to achieve bidirectional communication between master(s) and slave(s). A master (typically a microcontroller) initiates all data transfers to and from the MAX7300, and generates the SCL clock that synchronizes the data transfer (Figure 2). The MAX7300 SDA line operates as both an input and an open-drain output. A pullup resistor, typically 4.7kΩ, is required on SDA. The MAX7300 SCL line operates only as an input. A pullup resistor, typically 4.7kΩ, is required on SCL if there are multiple masters on the 2-wire interface, or if the master in a single-master system has an open-drain SCL output. Each transmission consists of a START condition (Figure 3) sent by a master, followed by the MAX7300 7-bit slave address plus R/W bit (Figure 6), a register address byte, one or more data bytes, and finally a STOP condition (Figure 3). www.maximintegrated.com ADDRESS CODE (HEX) START and STOP Conditions Both SCL and SDA remain high when the interface is not busy. A master signals the beginning of a transmission with a START (S) condition by transitioning SDA from high to low while SCL is high. When the master has finished communicating with the slave, it issues a STOP (P) condition by transitioning SDA from low to high while SCL is high. The bus is then free for another transmission (Figure 3). Bit Transfer One data bit is transferred during each clock pulse. The data on SDA must remain stable while SCL is high (Figure 4). Acknowledge The acknowledge bit is a clocked 9th bit, which the recipient uses to handshake receipt of each byte of data (Figure 5). Thus, each byte transferred effectively requires 9 bits. The master generates the 9th clock pulse, and the recipient pulls down SDA during the acknowledge clock pulse, such that the SDA line is sta-ble low during the high period of the clock pulse. When the master is transmitting to the MAX7300, the MAX7300 generates the acknowledge bit since the Maxim Integrated │ 7 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander PORT REGISTERS CONFIGURATION MASK REGISTER GPIO P4 TO P31 CONFIGURATION REGISTERS PORT CHANGE DETECTOR DATA R/W CE 8 GPIO DATA R/W 8 AD0 COMMAND REGISTER DECODE ADDRESS MATCHER AD1 7 8 8 DATA BYTE D0 D1 D2 D3 D4 COMMAND BYTE D5 D6 7 7-BIT DEVICE ADDRESS SDA SCL D7 D8 D9 D10 TO/FROM DATA REGISTERS D11 D12 D13 D14 D15 TO COMMAND REGISTERS R/W SLAVE ADDRESS BYTE DATA BYTE COMMAND BYTE Figure 1. MAX7300 Functional Diagram MAX7300 is the recipient. When the MAX7300 is transmitting to the master, the master generates the acknowledge bit since the master is the recipient. Slave Address The MAX7300 has a 7-bit-long slave address (Figure 6). The eighth bit following the 7-bit slave address is the RW bit. It is low for a write command and high for a read command. The first 3 bits (MSBs) of the MAX7300 slave address are always 100. Slave address bits A3, A2, A1, and A0 are selected by the address inputs, AD1 and AD0. These two input pins can be connected to GND, V+, SDA, or SCL. The MAX7300 has 16 possible slave www.maximintegrated.com addresses (Table 3), and therefore a maximum of 16 MAX7300 devices can share the same interface. Message Format for Writing the MAX7300 A write to the MAX7300 comprises the transmission of the MAX7300’s slave address with the R/W bit set to zero, followed by at least 1 byte of information. The first byte of information is the command byte. The command byte determines which register of the MAX7300 is to be written by the next byte, if received. If a STOP condition is detected after the command byte is received, then the MAX7300 takes no further action (Figure 7) beyond storing the command byte. Maxim Integrated │ 8 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander SDA tSU, STA tSU, DAT tLOW tHD, DAT SCL tBUF tHD, STA tSU, STO tHIGH tHD, STA tR tF REPEATED START CONDITION START CONDITION STOP CONDITION START CONDITION Figure 2. 2-Wire Serial Interface Timing Details SDA S P START CONDITION STOP CONDITION SCL Figure 3. Start and Stop Conditions SDA SCL DATA LINE STABLE; DATA VALID CHANGE OF DATA ALLOWED Figure 4. Bit Transfer Any bytes received after the command byte are considered data bytes. The first data byte goes into the internal register of the MAX7300 selected by the command byte (Figure 8). If multiple data bytes are transmitted before a STOP condition is detected, these bytes are generally stored in subsequent MAX7300 internal registers because the command byte address generally autoincrements (Table 4). Message Format for Reading The MAX7300 is read using the MAX7300’s internally stored command byte as address pointer, the same way the stored command byte is used as address pointer for www.maximintegrated.com a write. The pointer generally autoincrements after each data byte is read using the same rules as for a write (Table 4). Thus, a read is initiated by first configuring the MAX7300’s command byte by performing a write (Figure 7). The master can now read ‘n’ consecutive bytes from the MAX7300, with the first data byte being read from the register addressed by the initialized command byte (Figure 9). When performing read-after-write verification, remember to reset the command byte’s address because the stored control byte address generally has been autoincremented after the write (Table 4). Table 5 is the register address map. Maxim Integrated │ 9 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander CLOCK PULSE FOR ACKNOWLEDGMENT START CONDITION SCL 1 2 8 9 SDA BY TRANSMITTER S SDA BY RECEIVER Figure 5. Acknowledge SDA 1 0 0 A3 MSB A2 A1 A0 R/W ACK LSB SCL Figure 6. Slave Address Operation with Multiple Masters If the MAX7300 is operated on a 2-wire interface with multiple masters, a master reading the MAX7300 should use a repeated start between the write, which sets the MAX7300’s address pointer, and the read(s) that takes the data from the location(s). This is because it is possible for master 2 to take over the bus after master 1 has set up the MAX7300?s address pointer, but before master 1 has read the data. If master 2 subsequently changes, the MAX7300’s address pointer, then master 1’s delayed read can be from an unexpected location. Command Address Autoincrementing Address autoincrementing allows the MAX7300 to be configured with the shortest number of transmissions by minimizing the number of times the command address needs to be sent. The command address stored in the MAX7300 generally increments after each data byte is written or read (Table 4). www.maximintegrated.com Initial Power-Up On initial power-up, all control registers are reset and the MAX7300 enters shutdown mode (Table 6). Transition (Port Data Change) Detection Port transition detection allows any combination of the seven ports P24–P30 to be continuously monitored for changes in their logic status (Figure 10). A detected change is flagged on the transition detection mask register INT status bit, D7 (Table 10). If port P31 is configured as an output (Tables 1 and 2), then P31 also automatically becomes an active-high interrupt output (INT), which follows the condition of the INT status bit. Port P31 is set as output by writing bit D7 = 0 and bit D6 = 1 to the port configuration register (Table 1). Note that the MAX7300 does not identify which specific port(s) caused the interrupt, but provides an alert that one or more port levels have changed. The mask register contains 7 mask bits that select which of the seven ports P24–P30 are to be monitored (Table 10). Set the appropriate mask bit to enable that port for transition detect. Clear the mask bit if transi- Maxim Integrated │ 10 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander D15 D14 D13 D12 D11 D10 D9 COMMAND BYTE IS STORED ON RECEIPT OF STOP CONDITION ACKNOWLEDGE FROM MAX7300 S SLAVE ADDRESS 0 R/W A D8 A COMMAND BYTE P ACKNOWLEDGE FROM MAX7300 Figure 7. Command Byte Received ACKNOWLEDGE FROM MAX7300 D15 D14 D13 D12 D11 D10 HOW COMMAND BYTE AND DATA BYTE MAP INTO MAX7300’s REGISTER ACKNOWLEDGE FROM MAX7300 S SLAVE ADDRESS 0 A COMMAND BYTE D9 ACKNOWLEDGE FROM MAX7300 D8 D7 A D6 D5 D4 D3 D2 D1 D0 DATA BYTE A P 1 BYTE R/W AUTOINCREMENT MEMORY WORD ADDRESS Figure 8. Command and Single Data Byte Received tions on that port are to be ignored. Transition detection works regardless of whether the port being monitored is set to input or output, but generally, it is not particularly useful to enable transition detection for outputs. To use transition detection, first set up the mask register and configure port P31 as an output, as described above. Then enable transition detection by setting the M bit in the configuration register (Table 9). Whenever the configuration register is written with the M bit set, the MAX7300 updates an internal 7-bit snapshot register, which holds the comparison copy of the logic states of ports P24 through P30. The update action occurs regardless of the previous state of the M bit, so that it is not necessary to clear the M bit and then set it again to update the snapshot register. When the configuration register is written with the M bit set, transition detection is enabled and remains enabled until either the configuration register is written with the M bit clear, or a transition is detected. The INT status bit (transition detection mask register bit D7) goes low. Port P31 (if enabled as INT output) also goes low, if it was not already low. Once transition detection is enabled, the MAX7300 continuously compares the snapshot register against the changing states of P24 through P31. If a change on any of the monitored ports is detected, even for a short time (like a pulse), the INT status bit (transition detection mask register bit D7) is set. Port P31 (if enabled as INT output) also goes high. The INT output and INT status bit are not cleared if more changes occur or if the data pattern returns to its original snapshot condition. www.maximintegrated.com The only way to clear INT is to access (read or write) the transition detection mask register (Table 10). So if the transition detection mask register is read twice in succession after a transition event, the first time reads with bit D7 set (identifying the event), and the second time reads with bit D7 clear. Transition detection is a one-shot event. When INT has been cleared after responding to a transition event, transition detection is automatically disabled, even though the M bit in the configuration register remains set (unless cleared by the user). Reenable transition detection by writing the configuration register with the M bit set to take a new snapshot of the seven ports P24 to P30. External Component RISET The MAX7300 uses an external resistor, RISET, to set internal biasing. Use a resistor value of 39kΩ. Applications Information Low-Voltage Operation The MAX7300 operates down to 2V supply voltage (although the sourcing and sinking currents are not guaranteed), providing that the MAX7300 is powered up initially to at least 2.5V to trigger the device’s internal reset. Serial Interface Latency When a MAX7300 register is written through the I2C interface, the register is updated on the rising edge of SCL during the data byte’s acknowledge bit (Figure 5). The delay from the rising edge of SCL to the internal register being updated can range from 50ns to 350ns. Maxim Integrated │ 11 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander ACKNOWLEDGE FROM MAX7300 ACKNOWLEDGE FROM MAX7300 HOW COMMAND BYTE AND DATA BYTE MAP INTO MAX7300’s REGISTER D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 ACKNOWLEDGE FROM MAX7300 S SLAVE ADDRESS 0 COMMAND BYTE A DATA BYTE A A P ‘n’ BYTES R/W AUTOINCREMENT MEMORY WORD ADDRESS Figure 9. ‘n’ Data Bytes Received Table 3. MAX7300 Address Map PIN CONNECTION DEVICE ADDRESS AD1 AD0 A6 A5 A4 A3 A2 A1 A0 GND GND 1 0 0 0 0 0 0 GND V+ 1 0 0 0 0 0 1 GND SDA 1 0 0 0 0 1 0 GND SCL 1 0 0 0 0 1 1 V+ GND 1 0 0 0 1 0 0 V+ V+ 1 0 0 0 1 0 1 V+ SDA 1 0 0 0 1 1 0 V+ SCL 1 0 0 0 1 1 1 SDA GND 1 0 0 1 0 0 0 SDA V+ 1 0 0 1 0 0 1 SDA SDA 1 0 0 1 0 1 0 SDA SCL 1 0 0 1 0 1 1 SCL GND 1 0 0 1 1 0 0 SCL V+ 1 0 0 1 1 0 1 SCL SDA 1 0 0 1 1 1 0 SCL SCL 1 0 0 1 1 1 1 Table 4. Autoincrement Rules COMMAND BYTE ADDRESS RANGE x0000000 to x1111110 x1111111 PC Board Layout Considerations AUTOINCREMENT BEHAVIOR Command address autoincrements after byte read or written Command address remains at x1111111 after byte written or read Ensure that all the MAX7300 GND connections are used. For TQFN versions, connect the underside exposed pad to GND. A ground plane is not necessary, but may be useful to reduce supply impedance if the MAX7300 outputs are to be heavily loaded. Keep the track length from the ISET pin to the RISET resistor as short as possible, and take the GND end of the register either to the ground plane or directly to the GND pins. www.maximintegrated.com Power-Supply Considerations The MAX7300 operates with power-supply voltages of 2.5V to 5.5V. Bypass the power supply to GND with a 0.047µF capacitor as close to the device as possible. Add a 1µF capacitor if the MAX7300 is far away from the board’s input bulk decoupling capacitor. Maxim Integrated │ 12 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Table 5. Register Address Map COMMAND ADDRESS D15 D14 D13 D12 D11 D10 D9 D8 HEX CODE No-Op X 0 0 0 0 0 0 0 0x00 Configuration X 0 0 0 0 1 0 0 0x04 Transition Detect Mask X 0 0 0 0 1 1 0 0x06 Factory Reserved; do not write to this port X 0 0 0 0 1 1 1 0x07 Port Configuration P7, P6, P5, P4 X 0 0 0 1 0 0 1 0x09 Port Configuration P11, P10, P9, P8 X 0 0 0 1 0 1 0 0x0A Port Configuration P15, P14, P13, P12 X 0 0 0 1 0 1 1 0x0B Port Configuration P19, P18, P17, P16 X 0 0 0 1 1 0 0 0x0C Port Configuration P23, P22, P21, P20 X 0 0 0 1 1 0 1 0x0D Port Configuration P27, P26, P25, P24 X 0 0 0 1 1 1 0 0x0E Port Configuration P31, P30, P29, P28 X 0 0 0 1 1 1 1 0x0F Port 0 only (virtual port, no action) X 0 1 0 0 0 0 0 0x20 Port 1 only (virtual port, no action) X 0 1 0 0 0 0 1 0x21 Port 2 only (virtual port, no action) X 0 1 0 0 0 1 0 0x22 Port 3 only (virtual port, no action) X 0 1 0 0 0 1 1 0x23 Port 4 only (data bit D0. D7-D1 read as 0) X 0 1 0 0 1 0 0 0x24 Port 5 only (data bit D0. D7-D1 read as 0) X 0 1 0 0 1 0 1 0x25 Port 6 only (data bit D0. D7-D1 read as 0) X 0 1 0 0 1 1 0 0x26 Port 7 only (data bit D0. D7-D1 read as 0) X 0 1 0 0 1 1 1 0x27 Port 8 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 0 0 0 0x28 Port 9 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 0 0 1 0x29 Port 10 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 0 1 0 0x2A Port 11 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 0 1 1 0x2B Port 12 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 1 0 0 0x2C Port 13 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 1 0 1 0x2D Port 14 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 1 1 0 0x2E Port 15 only (data bit D0. D7-D1 read as 0) X 0 1 0 1 1 1 1 0x2F Port 16 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 0 0 0 0x30 Port 17 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 0 0 1 0x31 Port 18 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 0 1 0 0x32 Port 19 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 0 1 1 0x33 Port 20 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 1 0 0 0x34 Port 21 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 1 0 1 0x35 Port 22 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 1 1 0 0x36 Port 23 only (data bit D0. D7-D1 read as 0) X 0 1 1 0 1 1 1 0x37 Port 24 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 0 0 0 0x38 Port 25 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 0 0 1 0x39 REGISTER www.maximintegrated.com Maxim Integrated │ 13 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Table 5. Register Address Map (continued) COMMAND ADDRESS D15 D14 D13 D12 D11 D10 D9 D8 HEX CODE Port 26 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 0 1 0 0x3A Port 27 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 0 1 1 0x3B Port 28 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 1 0 0 0x3C Port 29 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 1 0 1 0x3D Port 30 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 1 1 0 0x3E Port 31 only (data bit D0. D7-D1 read as 0) X 0 1 1 1 1 1 1 0x3F 4 ports 4–7 (data bits D0–D3. D4–D7 read as 0) X 1 0 0 0 0 0 0 0x40 5 ports 4–8 (data bits D0–D4. D5–D7 read as 0) X 1 0 0 0 0 0 1 0x41 6 ports 4–9 (data bits D0–D5. D6–D7 read as 0) X 1 0 0 0 0 1 0 0x42 7 ports 4–10 (data bits D0–D6. D7 reads as 0) X 1 0 0 0 0 1 1 0x43 8 ports 4–11 (data bits D0–D7) X 1 0 0 0 1 0 0 0x44 8 ports 5–12 (data bits D0–D7) X 1 0 0 0 1 0 1 0x45 8 ports 6–13 (data bits D0–D7) X 1 0 0 0 1 1 0 0x46 8 ports 7–14 (data bits D0–D7) X 1 0 0 0 1 1 1 0x47 8 ports 8–15 (data bits D0–D7) X 1 0 0 1 0 0 0 0x48 8 ports 9–16 (data bits D0–D7) X 1 0 0 1 0 0 1 0x49 8 ports 10–17 (data bits D0–D7) X 1 0 0 1 0 1 0 0x4A 8 ports 11–18 (data bits D0–D7) X 1 0 0 1 0 1 1 0x4B 8 ports 12–19 (data bits D0–D7) X 1 0 0 1 1 0 0 0x4C 8 ports 13–20 (data bits D0–D7) X 1 0 0 1 1 0 1 0x4D 8 ports 14–21 (data bits D0–D7) X 1 0 0 1 1 1 0 0x4E 8 ports 15–22 (data bits D0–D7) X 1 0 0 1 1 1 1 0x4F 8 ports 16–23 (data bits D0–D7) X 1 0 1 0 0 0 0 0x50 8 ports 17–24 (data bits D0–D7) X 1 0 1 0 0 0 1 0x51 8 ports 18–25 (data bits D0–D7) X 1 0 1 0 0 1 0 0x52 8 ports 19–26 (data bits D0–D7) X 1 0 1 0 0 1 1 0x53 8 ports 20–27 (data bits D0–D7) X 1 0 1 0 1 0 0 0x54 8 ports 21–28 (data bits D0–D7) X 1 0 1 0 1 0 1 0x55 8 ports 22–29 (data bits D0–D7) X 1 0 1 0 1 1 0 0x56 8 ports 23–30 (data bits D0–D7) X 1 0 1 0 1 1 1 0x57 8 ports 24–31 (data bits D0–D7) X 1 0 1 1 0 0 0 0x58 7 ports 25–31 (data bits D0–D6. D7 reads as 0) X 1 0 1 1 0 0 1 0x59 6 ports 26–31 (data bits D0–D5. D6–D7 read as 0) X 1 0 1 1 0 1 0 0x5A 5 ports 27–31 (data bits D0–D4. D5–D7 read as 0) X 1 0 1 1 0 1 1 0x5B 4 ports 28–31 (data bits D0–D3. D4–D7 read as 0) X 1 0 1 1 1 0 0 0x5C 3 ports 29–31 (data bits D0–D2. D3–D7 read as 0) X 1 0 1 1 1 0 1 0x5D 2 ports 30–31 (data bits D0–D1. D2–D7 read as 0) X 1 0 1 1 1 1 0 0x5E 1 port 31 only (data bits D0. D1–D7 read as 0) X 1 0 1 1 1 1 1 0x5F REGISTER Note: Unused bits read as zero. www.maximintegrated.com Maxim Integrated │ 14 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Table 6. Power-Up Configuration REGISTER FUNCTION POWER-UP CONDITION Port Register Bits 4 to 31 GPIO Output Low Configuration Register ADDRESS CODE (HEX) REGISTER DATA D7 D6 D5 D4 D3 D2 D1 D0 0x24 to 0x3F X X X X X X X 0 Shutdown Enabled Transition Detection Disabled 0x04 0 0 X X X X X 0 All Clear (Masked Off) 0x06 X 0 0 0 0 0 0 0 Port Configuration P7, P6, P5, P4: GPIO Inputs without Pullup 0x09 1 0 1 0 1 0 1 0 Port Configuration P11, P10, P9, P8: GPIO Inputs without Pullup 0x0A 1 0 1 0 1 0 1 0 Port Configuration P15, P14, P13, P12: GPIO Inputs without Pullup 0x0B 1 0 1 0 1 0 1 0 Port Configuration P19, P18, P17, P16: GPIO Inputs without Pullup 0x0C 1 0 1 0 1 0 1 0 Port Configuration P23, P22, P21, P20: GPIO Inputs without Pullup 0x0D 1 0 1 0 1 0 1 0 Port Configuration P27, P26, P25, P24: GPIO Inputs without Pullup 0x0E 1 0 1 0 1 0 1 0 Port Configuration P31, P30, P29, P28: GPIO Inputs without Pullup 0x0F 1 0 1 0 1 0 1 0 Input Mask Register X = unused bits; if read, zero results. www.maximintegrated.com Maxim Integrated │ 15 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Table 7. Configuration Register Format REGISTER DATA FUNCTION ADDRESS CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0 Configuration Register 0x04 M 0 X X X X X S Table 8. Shutdown Control (S Data Bit D0) Format REGISTER DATA FUNCTION ADDRESS CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0 Shutdown 0x04 M 0 X X X X X 0 Normal Operation 0x04 M 0 X X X X X 1 Table 9. Transition Detection Control (M Data Bit D7) Format REGISTER DATA FUNCTION ADDRESS CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0 Disabled 0x04 0 0 X X X X X S Enabled 0x04 1 0 X X X X X S Table 10. Transition Detection Mask Register FUNCTION REGISTER ADDRESS (HEX) Mask Register 0x06 REGISTER DATA READ/ WRITE D7 D6 D5 D4 D3 D2 D1 D0 Read INT Status* Write Unchanged Port 30 mask Port 29 mask Port 28 mask Port 27 mask Port 26 mask Port 25 mask Port 24 mask *INT is automatically cleared after it is read. www.maximintegrated.com Maxim Integrated │ 16 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander GPIO INPUT CONDITIONING GPIO IN GPIO/PORT OUTPUT LATCH GPIO/PORT OUT INT STATUS STORED AS MSB OF MASK REGISTER P31 INT OUTPUT LATCH CLOCK PULSE AFTER EACH READ ACCESS TO MASK REGISTER R S CONFIGURATION REGISTER M BIT = 1 GPIO INPUT CONDITIONING P30 GPIO IN D Q GPIO/PORT OUT MASK REGISTER BIT 6 GPIO/PORT OUTPUT LATCH P29 GPIO INPUT CONDITIONING GPIO/PORT OUTPUT LATCH GPIO INPUT CONDITIONING P28 GPIO/PORT OUTPUT LATCH GPIO INPUT CONDITIONING P27 GPIO/PORT OUTPUT LATCH GPIO INPUT CONDITIONING P26 GPIO/PORT OUTPUT LATCH P25 GPIO INPUT CONDITIONING GPIO/PORT OUTPUT LATCH P24 GPIO INPUT CONDITIONING GPIO/PORT OUTPUT LATCH GPIO IN D Q GPIO/PORT OUT GPIO IN MASK REGISTER BIT 5 D Q GPIO/PORT OUT GPIO IN MASK REGISTER BIT 4 D Q GPIO IN D Q GPIO/PORT OUT GPIO IN MASK REGISTER BIT 2 D Q GPIO/PORT OUT GPIO IN GPIO/PORT OUT OR MASK REGISTER BIT 3 GPIO/PORT OUT MASK REGISTER BIT 1 D Q MASK REGISTER LSB CLOCK PULSE WHEN WRITING CONFIGURATION REGISTER WITH M BIT SET Figure 10. Maskable GPIO Ports P24 to P31 www.maximintegrated.com Maxim Integrated │ 17 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Pin Configurations (continued) 36 SSOP P27 P26 22 21 23 24 25 26 27 28 P4 P31 P5 P30 P6 P29 P7 P28 9 10 P17 8 7 P11 P15 P16 P25 15 SDA 22 14 SCL 23 13 P23 AD1 24 12 P22 V+ 25 11 P21 MAX7300 P24 ISET 26 10 P20 GND 27 9 P19 GND 28 8 P18 7 19 P22 P17 20 P23 P21 18 P26 21 P24 P20 17 16 P19 16 N.C. TOP VIEW 6 22 P25 P16 23 P26 P27 P17 14 P18 15 P23 P22 P21 P20 P19 P18 40 TQFN-EP 17 24 P27 5 25 P28 P16 13 P15 26 P7 P15 12 6 P11 11 P28 27 P29 P24 12 11 18 P14 10 AD0 4 28 P6 P14 9 5 P10 GND GND 4 29 P30 3 8 P29 P13 P30 30 P5 19 7 20 6 P9 3 31 P31 P12 MAX7300 2 MAX7300 33 34 35 36 37 38 39 40 P13 32 P4 N.C. P25 20 19 18 17 16 15 14 13 P12 33 SDA 5 2 4 P8 31 32 1 AD0 N.C. SDA SCL AD1 V+ ISET GND P8 P12 P9 P13 P10 P14 34 SCL P31 3 21 35 AD1 GND 1 2 29 36 V+ GND ADO ISET 1 30 TOP VIEW 28 TQFN-EP www.maximintegrated.com Maxim Integrated │ 18 MAX7300 Chip Information PROCESS: CMOS www.maximintegrated.com 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 28 SSOP A28+1 21-0056 90-0095 28 TQFN-EP T2855+6 21-0140 90-0026 36 SSOP A36+4 21-0040 90-0098 40 TQFN-EP T4066+5 21-0141 90-0055 Maxim Integrated │ 19 MAX7300 2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port I/O Expander Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 7 9/11 Updated Ordering Information, Absolute Maximum Ratings, Pin Description, Table 1, and Package Information sections 1, 2, 6, 7, 19 8 5/14 No /V OPNs; removed automotive reference from Applications section 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2014 Maxim Integrated Products, Inc. │ 20