| | PIN. NO. | | |
| MNEMONIC | LCC | LQFP | TYPE | NAME AND FUNCTION |
| Vss | 1. 22 | 16 | l | Ground: OV reference. |
| VDD | 23 44 | 17 | l | Power Supply: This is the power supply voltage for normal, idle, and power down operation. |
| PO.O - P0.7 | 43-36 | 37-30 | l/0 | Port 0: Port o is an 8-bit l/0 port with a user-configurable output type. Port o latches have ls written to them and are configured in the quasi-bidirectional mode during reset. The operation of port o pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on l/0 port configuration and the DC Electrical Characteristics for details. When the external program/data bus is used, Port o becomes the multiplexed low data/instruction byte and address lines 4 through 11. |
| P1.0 - P1.7 | 2-9 2 3 4 5 6 7 8 9 | 40-44, 1-3 40 41 42 43 44 1 2 3 | [/0 0 o o o I o 1/0 | Port l: Port l is an 8-bit l/0 port with a user-configurable output type. Port l latches have ls written to them and are configured in the quasi-bidirectional mode during reset. The operation of port l pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on l/0 port configuration and the DC Electrical Characteristics for details. Port l also provides special functions as described below. AO/WRH: Address bit o of the external address bus when the external data bus is configured for an 8 bit width. When the external data bus is configured for a 16 bit width, this pin becomes the high byte write strobe. A1: Address bit l of the external address bus. A2: Address bit 2 0f the external address bus. A3: Address bit 3 0f the external address bus. RxDl (P1.4): Receiver input for serial port l. TxDl (P1.5): Transmitter output for serial port l. T2 (P1.6): Timer/counter 2 external count input/clockout. T2EX (P1.7): Timer/counter 2 reload/capture/direction control |
| P2.0 - P2.7 | 24-31 | 18-25 | 1/0 | Port 2: Port 2 is an 8-bit l/0 port with a user-configurable output type. Port 2 latches have ls written to them and are configured in the quasi-bidirectional mode during reset. The operation of port 2 pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on l/0 port configuration and the DC Electrical Characteristics for details. When the external program/data bus is used in 16-bit mode, Port 2 becomes the multiplexed high data/instruction byte and address lines 12 through 19. When the external program/data bus is used in 8-bit mode, the number of address lines that appear on port 2 is user programmable. |
| P3.0 - P3.7 | 11, 13-19 11 13 14 15 16 17 18 19 | 5, 7-13 5 7 8 9 10 11 12 13 | 1/0 I o I I 1/0 1/0 0 o | Port 3: Port 3 is an 8-bit l/0 port with a user configurable output type. Port 3 latches have ls written to them and are configured in the quasi-bidirectional mode during reset. the operation of port 3 pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on l/0 port configuration and the DC Electrical Characteristics for details. Port 3 also provides various special functions as described below. RxDO (P3.0): Receiver input for serial port 0. TxDO (P3.1): Transmitter output for serial port 0. INTO (P3.2): External interrupt o input. INTl (P3.3): External interrupt l input. TO (P3.4): Timer o external input, or timer o overflow output. T1/BUSW (P3.5): Timer l external input, or timer l overflow output. The value on this pin is latched as the external reset input is released and defines the default external data bus width (BUSW). 0 = 8-bit bus and l = 16-bit bus. WRL (P3.6): External data memory low byte write strobe. RD (P3.7): External data memory read strobe. |
| RST | 10 | 4 | l | Reset: A low on this pin resets the microcontroller, causing l/0 ports and peripherals to take on their default states, and the processor to begin execution at the address contained in the reset vector. Refer to the section on Reset for details. |
| ALE | 33 | 27 | 1/0 | Address Latch Enable: A high output on the ALE pin signals external circuitry to latch the address portion of the multiplexed address/data bus. A pulse on ALE occurs only when it is needed in order to process a bus cycle. |
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