Epson Research and Development
Page 7
Vancouver Design Center
MC68340 Interface Considerations
S1D13503
Issue Date: 01/01/30
X18A-G-004-04
2.2 PAL Equations
The PAL is programmed with the following equations:
1.
With direct-mapping I/O occupying locations from 00000000h to 0000000Fh and A4 to A9 decoded internally to
S1D13503;
IOCS# = !(!CS3 & !A17 & !A16 & !A15 & !A14 & !A13 & !A12 & !A11 & !A10)
2.
With memory locations from 00020000h to 003FFFFh and A17 to A19 decoded internally to S1D13503;
MEMCS# = CS3
3.
BHE# becomes valid for two conditions:
1. 16-bit or 32-bit cycle, i.e., SIZ0=0
2. 8-bit cycle with odd byte access, i.e., SIZ0=1 and A0=1;
BHE# = SIZ0 & !A0
2.3 S1D13503 Default Setup
Configuration Options
1.
VD15 - VD13 = 001
memory decoding for locations 20000h - 3FFFFh
2.
VD12 - VD4 = 000000xxx
I/O decoding for locations 0000000000b - 0000001111b
3.
VD3 = 1
byte swap of high and low bytes
4.
VD2 = 1
MC68K interface
5.
VD1 = 1
direct-mapping I/O
6.
VD0 = 1
16-bit bus interface
Where x = don’t care; 1 = pull-up with a 10K resistor; 0 = no pull-up resistor
Note
The states of these data pins are internally latched during RESET.
Register Setting
AUX[1] bit 1 = 0 for 16-bit memory interface (must be 16-bit with a 16-bit bus).
electronic components distributor