GMS90 Hynix Semiconductor, GMS90 Datasheet - Page 52

• Manufacturer Part Number: GMS90
• Description: 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: Hynix Semiconductor

encryption table is disabled. However, the other security bit can still be programmed. Note that the EA/V
must not be allowed to go above the maximum specified V
above that voltage can cause permanent damage to the device. The V
glitches and overshoot.
Figure 12. Programming Configuration
Program Verification
If security bit 2 has not been programmed, the on-chip program memory can be read out for program verifica-
tion. The address of the program memory location to be read is applied to ports 1 and 2 as shown in Figure 15.
The other pins are held at the "Verify Code Data" levels indicated in Table 11. The contents of the address lo-
cation will be emitted on port 0 for this operation. If the encryption table has been programmed, the data pre-
sented at port 0 will be the exclusive NOR of the program byte with one of the encryption bytes. The user will
have to know the encryption table contents in order to correctly decode the verification data. The encryption
table itself cannot be read out.
48
4~6MHz
GMS97X51/52:
GMS97X54/56/58:
NOTE:
A14
1
1
1
A0-A7
A8-A13
P1
P2.0
-P2.5
P3.4
RST
P3.6
P3.7
XTAL2
XTAL1
V
SS
100 s
100 s
ALE/PROG
PP
EA/V
level for any amount of time. Even a narrow glitch
PSEN
25 pulses to GND
10 pulses to GND
P2.7
P2.6
V
P0
CC
PP
PP
PROGRAM DATA
source should be well regulated and free
+5V
+12.75V
0
1
1
NOTE
Dec. 1998 Ver 3.0
GMS90 Series
PP
pin