Table of Contents
Advertisement
Epson Research and Development
Vancouver Design Center
1.2 PAL Equations
The PAL is programmed with the following equations:
1.
As stated above, the default I/O address is from 0310h to 0311h. The SED1352F0B provides internal decoding of ad-
dress bits A0 to A9, therefore minimal external circuitry is necessary to provide signals IOCS# and IOCS16#
IOCS# is required by the SED1352 to indicate a valid IO cycle. In an ISA bus environment, valid IO decoding must
include addresses A15-A0. Given this example, addresses A10-15 must all be '0' and AEN must also be '0'.
IOCS# = !(!AEN & !A15 & !A14 & !A13 & !A12 & !A11 & !A10)
2.
As the SED1352 is capable of 16-bit IO access, the IOCS16# bus signal must be driven externally to indicate such a
cycle. As stated in the ISA specification, the IOCS16# is a straight address decode without qualification.
IOCS16EN# = !(!IOCS# & A9 & A8 & !A7 & !A6 & !A5 & A4 & !A3 & !A2 & !A1)
3.
With 128Kbytes of display memory and A17 to A19 decoded internally to SED1352F0B;
MEMCS# = !REFRESH
1.3 Additional Discrete Logic Description
1.
As shown in Figure 1, the 74LS688 is configured as a memory decoder with valid addresses between 0Cxxxxh and
0Dxxxxh.
2.
The 74LS09 is used simply to provide the Open-Collector outputs necessary for the IOCS16# and MEMCS16# sig-
nals.
1.4 SED1352F0B Default Setup
1.4.1 Configuration Options
1.
VD15 - VD13 = 110
2.
VD12 - VD4 = 110001000
3.
VD3 = 0
4.
VD2 = 0
5.
VD1 = 0
6.
VD0 = 1
Where 1 = pull-up with a 10K resistor; 0 = no pull-up resistor
Note
The states of these data pins are internally latched during RESET.
1.4.2 Register Setting
AUX[1] bit 1 = 0 for 16-bit memory interface (must be 16-bit with a 16-bit bus).
ISA Bus Interface Considerations
Issue Date: 98/10/08
memory decoding for locations $C and $D segments
I/O decoding for locations 1100010000b - 1100010001b
no byte swap of high and low bytes
ISA Bus interface, i.e. non- MC68K interface
indexing I/O
16-bit bus interface
Page 7
SED1352F0B
X16-AN-003-05
Advertisement
Chapters
Table of Contents
