GMS90 Series
EPROM CHARACTERISTICS
The GMS97C5X, 97L5X are programmed by using a modified Quick-Pulse ProgrammingTM algorithm. It dif-
fers from older methods in the value used for VPP (programming supply voltage) and in the width and number
of the ALE/PROG pulses. The GMS97C5X, 97L5X contains two signature bytes that can be read and used by
an EPROM programming system to identify the device. The signature bytes identify the device as an manufac-
tured by LGS. Table 11 shows the logic levels for reading the signature byte, and for programming the program
memory, the encryption table, and the security bits. The circuit configuration and waveforms for quick-pulse
programming are shown in Figure 12 and Figure 13. Figure 14 show the circuit configuration for normal pro-
gram memory verification.
Reading the Signature Bytes :
The GMS97X51/52 signature bytes in locations 030H and 031H, the GMS97X54/56/58 signature bytes in loca-
tions 030H and 060H. To read these bytes follow the procedure for EPROM verify, except that P3.6 and P3.7
need to be pulled to a logic low.
The values are:
Device
Location
Contents
Remarks
GMS97X51
30H
31H
E0H
73H
Manufacturer ID
Device ID
GMS97X52
GMS97X54
GMS97X56
GMS97X58
30H
31H
E0H
71H
Manufacturer ID
Device ID
30H
60H
E0H
54H
Manufacturer ID
Device ID
30H
60H
E0H
56H
Manufacturer ID
Device ID
30H
60H
E0H
58H
Manufacturer ID
Device ID
Quick-pulse programming
The setup for microcontroller quick-pulse programming is shown in Figure 13. Note that the GMS97C5X,
97L5X is running with a 4 to 6MHz oscillator. The reason the oscillator needs to be running is that the device
is executing internal address and program data transfers.
The address of the EPROM location to be programmed is applied to ports 1 and 2, as shown in Figure 12. The
code byte to be programmed into that location is applied to port 0, RST, PSENand pins of port 2 and 3 in Table
11 are held at the "Program Code Data" levels indicated in Table 11. The ALE/PROGis pulsed low 25 times(10
times for 97X54/56/58) as shown Figure 13.
To program the encryption table, repeat the 25 pulses (10 pulses for 97X54/56/58) programming sequence for
addresses 0 through 1FH(3FH for 97X54/56/58), using the "Program Encryption Table" levels. Do not forget
that after the encryption table is programmed, verification cycles will produce only encrypted data.
To program the security bits, repeat the 25 pulses (10 pulses for 97X54/56/58) programming sequence using the
"Pgm Security Bit" levels after one security bit is programmed, further programming of the code memory and
Dec. 1998 Ver 3.0
47
HYNIX [ HYNIX SEMICONDUCTOR ]
