Epson Research and Development Page 19
Vancouver Design Center
Interfacing to the Motorola MPC821 Microprocessor S1D13504
Issue Date: 01/02/02 X19A-G-010-05
4.4 Register/Memory Mapping
The S1D13504 is a memory mapped device. The DRAM on the MPC821 ADS board
extends from address 0h through 3F FFFFh, so the S1D13504 must be addressed starting
at 40 0000h. A total of 4M bytes of address space is used, where the lower 2M bytes
(from 40 0000h through 5F FFFFh) is reserved for the S1D13504 on-chip registe rs and t he
upper 2M bytes (from 60 0000h through 7F FFFFh) is used for the S1D13504 display
buffer.
4.5 MPC821 Chip Select Configuration
Chip select 4 is used to control the S1D13504. The following options are selected in the
base address register (BR4):
BA[0:16] = 0000 0000 0100 0000 0 set starting address of S1D13504 to 40 0000h.
AT[0:2] = 0 ignore address type bits.
PS[0:1] = 1:0 memory port size is 16-bit.
PARE = 0 disable parity checking.
WP = 0 disable write protect.
MS[0:1] = 0:0 select General Purpose Chip Select module to control this ch i p select.
V = 1 set valid bit to enable chip select.
The following options were selected in the op tion register (OR4):
AM[0:16] = 1111 1111 1100 0000 0 mask all but upper 10 address bits; S1D13504
consumes 4M byte of address space.
ATM[0:2] = 0 ignore address type bits.
CSNT = 0 normal CS/WE negation.
ACS[0:1] = 1:1 delay CS assertion by ½ clock cycle from address lines.
BI = 1 assert Burst Inhibit.
SCY[0:3]= 0 wait state selection; this field is ignored since external transfer
acknowledge is used; see SETA below.
SETA = 1 the S1D13504 generates an external transfer acknowledge using the
WAIT# line.
TRLX = 0 normal timing.
EHTR = 0 normal timing.