AMD AM186EM User Manual page 39

Table 3-1 PIO Pin Assignments—Numeric Listing
PIO No.
0
1
2
3
4
5
6
(1)
7
(1)
8
(1)
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
(1,2)
26
27
28
(1,2)
29
30
31
Notes:
1. These pins are used by emulators. (Emulators also use S2–S0 , RES , NMI, CLKOUTA, BHE ,
ALE, AD15–AD0, and A16–A0.
2. These pins revert to normal operation if BHE/ADEN (Am186EM) or RFSH2/ADEN (Am188EM)
is held Low during power-on reset.
3. When used as a PIO, input with pullup option available.
4. When used as a PIO, input with pulldown option available.
The A19–A17 address pins default to normal operation on power-on
reset, allowing the processor to correctly begin fetching instructions at
the boot address FFFF0h. The DT/R, DEN, and SRDY pins also default
to normal operation on power-on reset.
Associated Pin Power-On Reset Status
TMRIN1 Input with pullup
TMROUT1 Input with pulldown
PCS6/A2 Input with pullup
PCS5/A1 Input with pullup
DT/R
Normal operation
DEN
Normal operation
SRDY
Normal operation
A17
Normal operation
A18
Normal operation
A19
Normal operation
TMROUT0 Input with pulldown
TMRIN0 Input with pullup
DRQ0 Input with pullup
DRQ1 Input with pullup
MCS0 Input with pullup
MCS1 Input with pullup
PCS0 Input with pullup
PCS1 Input with pullup
PCS2 Input with pullup
PCS3 Input with pullup
SCLK Input with pullup
SDATA Input with pullup
SDEN0 Input with pulldown
SDEN1 Input with pulldown
MCS2 Input with pullup
MCS3/RFSH Input with pullup
UZI Input with pullup
TXD Input with pullup
RXD Input with pullup
S6/CLKDIV2 Input with pullup
INT4 Input with pullup
INT2 Input with pullup
System Overview
(3)
(3)
(4)
(3)
(3)
(3)
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