HMS87C1304A Datasheet, PDF (61/70 Pages) Hynix Semiconductor – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
HMS87C1304A/HMS87C1302A
18. 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 18-1 .
Internal RAM is not affected by reset. When V_DD 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 8-1 .
Oscillator
(X_IN pin)
RESET
ADDRESS
BUS
DATA
BUS
1234567
?
??
?
FFFE FFFF Start
?
ry _{Stabilizing Time}
t_ST = 64mS at 4MHz
? ? ? FE ADL ADH OP
RESET Process Step
MAIN PROGRAM
Prelimina ^{Figure 18-1 Timing Diagram after RESET}
Jan. 2001
Preliminary
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