PIC18F97J60_11 Datasheet, PDF (115/492 Pages) Microchip Technology – 64/80/100-Pin, High-Performance, 1-Mbit Flash Microcontrollers with Ethernet

PIC18F97J60 FAMILY
8.0 EXTERNAL MEMORY BUS
Note:
The external memory bus is not
implemented on 64-pin and 80-pin
devices.
The External Memory Bus (EMB) allows the device to
access external memory devices (such as Flash,
EPROM, SRAM, etc.) as program or data memory. It
supports both 8 and 16-Bit Data Width modes, and
three address widths of up to 20 bits.
The bus is implemented with 28 pins, multiplexed
across four I/O ports. Three ports (PORTD, PORTE
and PORTH) are multiplexed with the address/data bus
for a total of 20 available lines, while PORTJ is
multiplexed with the bus control signals.
A list of the pins and their functions is provided in
Table 8-1.
TABLE 8-1: PIC18F96J60/96J65/97J60 EXTERNAL MEMORY BUS – I/O PORT FUNCTIONS
Name
Port
Bit
External Memory Bus Function
RD0/AD0
PORTD
0
Address Bit 0 or Data Bit 0
RD1/AD1
PORTD
1
Address Bit 1 or Data Bit 1
RD2/AD2
PORTD
2
Address Bit 2 or Data Bit 2
RD3/AD3
PORTD
3
Address Bit 3 or Data Bit 3
RD4/AD4
PORTD
4
Address Bit 4 or Data Bit 4
RD5/AD5
PORTD
5
Address Bit 5 or Data Bit 5
RD6/AD6
PORTD
6
Address Bit 6 or Data Bit 6
RD7/AD7
PORTD
7
Address Bit 7 or Data Bit 7
RE0/AD8
PORTE
0
Address Bit 8 or Data Bit 8
RE1/AD9
PORTE
1
Address Bit 9 or Data Bit 9
RE2/AD10
PORTE
2
Address Bit 10 or Data Bit 10
RE3/AD11
PORTE
3
Address Bit 11 or Data Bit 11
RE4/AD12
PORTE
4
Address Bit 12 or Data Bit 12
RE5/AD13
PORTE
5
Address Bit 13 or Data Bit 13
RE6/AD14
PORTE
6
Address Bit 14 or Data Bit 14
RE7/AD15
PORTE
7
Address Bit 15 or Data Bit 15
RH0/A16
PORTH
0
Address Bit 16
RH1/A17
PORTH
1
Address Bit 17
RH2/A18
PORTH
2
Address Bit 18
RH3/A19
PORTH
3
Address Bit 19
RJ0/ALE
PORTJ
0
Address Latch Enable (ALE) Control bit
RJ1/OE
PORTJ
1
Output Enable (OE) Control bit
RJ2/WRL
PORTJ
2
Write Low (WRL) Control bit
RJ3/WRH
PORTJ
3
Write High (WRH) Control bit
RJ4/BA0
PORTJ
4
Byte Address (BA0) Bit 0
RJ5/CE
PORTJ
5
Chip Enable (CE) Control bit
RJ6/LB
PORTJ
6
Lower Byte Enable (LB) Control bit
RJ7/UB
PORTJ
7
Upper Byte Enable (UB) Control bit
Note: For the sake of clarity, only I/O port and external bus assignments are shown here. One or more additional
multiplexed features may be available in some pins.
 2011 Microchip Technology Inc.
DS39762F-page 115