
PROM VERSION
7702/7703 Group User’s Manual
19–19
19.5 Usage precaution
19.5.4 Bus timing and EPROM mode
The PROM versions shown in Tables 19.5.1 and 19.5.2 have the different bus timing from other PROM
versions, mask ROM, external ROM versions. Additionally, they can use 256K mode as EPROM mode
though its PROM size is 32 Kbytes or less.
Table 19.5.1 PROM versions having peculiar bus timing (16MHz version)
Bus timing
Type name
M37702E2AXXXFP
M37702E2AFS
M37702E4AXXXFP
M37702E4AFS
tpzx(E – P1Z), tpzx(E – P2Z)
f(XIN)
≤ 8 MHz
8MHz < f(XIN)
≤ 16 MHz
Limits: 50 ns
Limits: 25 ns
Formulas:
– 6.25
1 ! 109
2 ! f(XIN)
– 12.5
1 ! 109
2 ! f(XIN)
Table 19.5.2 PROM versions having peculiar bus timing (Low voltage version)
(1) Bus timing
The limits and formulas of the PROM versions having the peculiar bus timing which is different from
other PROM versions are shown in Tables 19.5.1 and 19.5.2.
When the user is planning to use the product shown in Tables 19.5.1 and 19.5.2 for evaluation or
in early production and replace it later with the mask ROM version, we recommend to use the
substitute shown in Table 19.5.3 for evaluation or in early production.
However, the substitute for the low voltage version has the larger ROM and RAM size. Make sure
of its memory usage. The substitute for the 16 MHz version has the higher frequency of external
clock input. There are no precaution about its operation.
Type name
M37702E2LXXXGP
M37702E4LXXXFP
1 ! 109
2 ! f(XIN)
– 12.5
1 ! 109
2 ! f(XIN)
50 +
– 62.5
tpzx(E – P1Z), tpzx(E – P2Z)
td(P0A – E), td(P1A – E), td(P2A – E),
td(BHE – E), td(R/W – E)
Limits: 50 ns
Formulas:
Bus timing
Table 19.5.3 Substitutes
Type name to be used
Substitute
Remark
M37702E2AXXXFP M37702E2BXXXFP The substitute has the higher frequency of external clock input.
M37702E2AFS
M37702E2BFS
M37702E4AXXXFP M37702E4BXXXFP
M37702E4AFS
M37702E4BFS
M37702E2LXXXGP M37702E4LXXXGP The substitute has the larger ROM and RAM size.
M37702E4LXXXFP M37702E6LXXXFP
(2) EPROM mode
The products shown in Table 19.5.1 can use only 256K mode as the EPROM mode. Do not use 1M
mode.