Signal Description
MOTOROLA
MC68307 USER’S MANUAL
2-15
DTACK
Data Acknowledge
Bidirectional
HALT
System Halt
Bidirectional
RESET
System Reset
Bidirectional
RSTIN
Power-On Reset
Input
CS0
Chip Select 0 (ROM)
Output
CS1
Chip Select 1 (RAM)
Output
CS2/CS2A
Chip Select 2 (Peripherals)
Output
CS3
Chip Select 3 (8051)
Output
ALE
8051-Address Latch Enable
Output
RD
8051-Bus Read
Output
WR
8051-Bus Write
Output
EXTAL
External Clock/Crystal In
Input
XTAL
External Crystal
Output
CLKOUT
Clock to System
Output
BUSW0
Initial Data Bus Width for CS0
Input
CS2B/PA0
Chip Select 2B/I/O Port A Bit 0
Bidirectional
CS2C/PA1
Chip Select 2C/I/O Port A Bit 1
Bidirectional
CS2D/PA2
Chip Select 2D/I/O Port A Bit 2
Bidirectional
TOUT1/PA3
Timer 1 Output/I/O Port A Bit 3
Bidirectional
TOUT2/PA4
Timer 2 Output/I/O Port A Bit 4
Bidirectional
BR/PA5
Bus Request Input/I/O Port A Bit 5
Bidirectional
BG/PA6
Bus Grant Output/I/O Port A Bit 6
Bidirectional
BGACK/PA7
Bus Grant Acknowledge Output/I/O Port A Bit 7
Bidirectional
IRQ7
Interrupt Level 7
Input
SCL/PB0
Serial M-Bus Clock/Port B Bit 0
Bidirectional
SDA/PB1
Serial M-Bus Data/Port B Bit 1
Bidirectional
TxD/PB2
UART Transmit Data/Port B Bit 2
Bidirectional
RxD/PB3
UART Receive Data/Port B Bit 3
Bidirectional
RTS/PB4
Request-to-Send/Port B Bit 4
Bidirectional
CTS/PB5
Clear-To-Send/Port B Bit 5
Bidirectional
TIN1/PB6
Timer 1 Input/Port B Bit 6
Bidirectional
TIN2/PB7
Timer 2 Input/Port B Bit 7
Bidirectional
INT1/PB8
Interrupt In 1/Port B Bit 8
Bidirectional
INT2/PB9
Interrupt In 2/Port B Bit 9
Bidirectional
INT3/PB10
Interrupt In 3/Port B Bit 10
Bidirectional
INT4/PB11
Interrupt In 4/Port B Bit 11
Bidirectional
INT5/PB12
Interrupt In 5/Port B Bit 12
Bidirectional
INT6/PB13
Interrupt In 6/Port B Bit 13
Bidirectional
INT7/PB14
Interrupt In 7/Port B Bit 14
Bidirectional
INT8/PB15
Interrupt In 8/Port B Bit 15
Bidirectional
Table 2-11. Signal Index (Continued)
Pin Name
Description of Pin Function(s)
Direction