sed1355 ETC-unknow, sed1355 Datasheet - Page 107

• Manufacturer Part Number: sed1355
• Description: Sed1355 Embedded Ramdac Lcd/crt Controller
• Manufacturer: ETC-unknow

Epson Research and Development
Vancouver Design Center
8.2.2 Memory Configuration Registers
bits 6-4
bit 2
bit 0
Hardware Functional Specification
Issue Date: 99/05/18
Memory Configuration Register
REG[01h]
n/a
DRAM Refresh Rate
Refresh Rate
Bit 2
Select Bits [2:0]
000
001
010
011
100
101
110
111
DRAM Refresh Rate Select Bits [2:0]
These bits specify the divisor used to generate the DRAM refresh rate from the input clock (CLKI).
WE# Control
When this bit = 1, 2-WE# DRAM is selected.
When this bit = 0, 2-CAS# DRAM is selected.
Memory Type
When this bit = 1, FPM-DRAM is selected.
When this bit = 0, EDO-DRAM is selected.
This bit should be changed only when there are no read/write DRAM cycles. This condition occurs
when all of the following are true: the Display FIFO is disabled (REG[23h] bit 7 = 1), and the Half
Frame Buffer is disabled (REG[1Bh] bit 0 = 1), and the Ink/Cursor is inactive
(Reg[27h] bits 7-6 = 00). This condition also occurs when the CRT and LCD enable bits (Reg[0Dh]
bits 1-0) have remained 0 since chip reset. For further programming information, see SED1355
Programming Notes and Examples, document number X23A-G-003-xx.
Refresh Rate
Bit 1
CLKI Frequency
Table 8-2: DRAM Refresh Rate Selection
Divisor
1024
2048
4096
8192
128
256
512
Refresh Rate
Bit 0
64
Example Refresh Rate
n/a
for CLKI = 33MHz
520 kHz
260 kHz
130 kHz
65 kHz
33 kHz
16 kHz
8 kHz
4 kHz
WE# Control
256 refresh cycles at
Example period for
CLKI = 33MHz
n/a
0.5 ms
16 ms
32 ms
64 ms
1 ms
2 ms
4 ms
8 ms
Memory Type
X23A-A-001-11
SED1355
Page 101
RW