GMS81C2020 Datasheet, PDF (81/92 Pages) Hynix Semiconductor – CMOS Single-Chip 8-Bit Microcontroller with A/D Converter & VFD Driver

Hyundai Micro Electronics
GMS81C2020/GMS81C2120
22. RESET
The reset input is the RESET pin, which is the input to a
Schmitt Trigger. A reset in accomplished by holding the
RESET pin low for at least 8 oscillator periods, while the
oscillator running. After reset, 64ms (at 4 MHz) add with
7 oscillator periods are required to start execution as shown
in Figure 26-2 .
Internal RAM is not affected by reset. When VDD is
turned on, the RAM content is indeterminate. Therefore,
this RAM should be initialized before reading or testing it.
Initial state of each register is shown as Table 11-3 .
Oscillator
(XI pin)
RESET
ADDRESS
BUS
DATA
BUS
1234567
?
??
?
FFFE FFFF Start
?
Stabilization Time
t_ST = 64mS at 4MHz
? ? ? FE ADL ADH OP
RESET Process Step
MAIN PROGRAM
Figure 22-1 Timing Diagram after RESET
Nov. 1999 Ver 0.0
preliminary
81