Limited Isa; Rtc - Epson SCE8720C Series Hardware Manual

CARD-PCI/GX Hardware Manual

4.10 LIMITED ISA

SCE8720C's LIMITED ISA bus is different from standard ISA as follows.
1) No master function provided.
2) Memory area is only 1MB, from 0000h to FFFFFh.
3) No DMA function provided. (However, for FDD access, DMA is used.)
4) The lower 16-bit address (SA0-15) is multiplexed to the data bus SD/SA[15:0] to be
output. Therefore, in order to obtain SA[15:0], SD/SA[15:0] must be latched by the
latch signal (SALATCH).
5) The following signals are not supported.
BALE, SCLK, OSC, REFRESH#, IOCHK#, 0WS#
(SMEMW# can be generated from other signals.)
6) SCE8720C's ISA output is 3.3V max.
Since the IC power supply, which drives the ISA bus, is 3.3V, SCE8720C's ISA
output level is 3.3V maximum. Input signal level is 5V-tolerant.
7) IRQ5, 9, 10 and 11 for the 280-pin connector, and IRQ3, 4, 7 and 15 for the 20-pin
connector are supported.
Reference 8.2 IO extension of ISA bus

4.11 RTC

MC146818A-compatible RTC function is built in the Super IO inside SCE8720C.
When V is supplied, it is supplied to the RTC power supply, and when V
CCSTB
OFF, the power supply is switched to the battery power supply, V
switching circuit is inside SCE8720C, connect V
Protection resistance applying to UL is also built-in.
46
and V
CCBAK
EPSON
. Since this
CCBAK
directly to SCE8720.
CCSTB
is
CCSTB
Rev.A