Z85233 Datasheet, PDF (165/317 Pages) Zilog, Inc. – The Zilog SCC Serial Communication Controller

Application Note
The Z180™ Interfaced with the SCC at MHZ
(Continued)
HCT138
G
/Y9
A9
/G2A
/Y6
A18
/G2B
/Y5
/Y4
A17
C
/Y3
A16
B
/Y2
A15
A
/Y1
/Y0
/38000 ~
/30000 ~
/28000 ~
/20000 ~
/18000 ~
/10000 ~
/08000 ~ To 55257 /E Pin
/00000 ~ To 27C256 /E Pin
/RD
/MREQ
/WR
* /MEMR To 27C56 /OE,
55257 /OE Pin
* /MEMW To 55257 /WE Pin
* /RD to /OE Pin of 27C256 and 55257
/WR To /WE Pin of 55257
Figure 4a. Memory Interface Logic
/USRRAM
/IORQ
A15
/USRROM
4.7 K Ω x2
HCT10
/CSRAM To 55257 /CE Pin
/CSROM To 27C256 /CE Pin
Figure 4b. Memory Interface Logic
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UM010901-0601