Sonic Alert msm80154s CPU internal status by reset, MSM80C154S/MSM83C154S reset internal status

Models: msm83c154s msm85c154hvs msm80154s

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3.2.3 CPU internal status by reset

When a reset signal is applied to the CPU with normal voltage applied to the MSM80C154S/ MSM83C154S VCC power supply pin, ports 0, 1, 2, and 3 are set to “1” (input mode) even if XTAL1·2 oscillation has been stopped. The output status of the ALE andPSEN pins also becomes “1”. The CPU is then reset after normal XTAL1·2 oscillation has resumed. The internal CPU status when the CPU is reset is shown in Table 3-1.

Table 3-1 MSM80C154S/MSM83C154S reset internal status

Register Name

Register Reset Status

PC

0000H

 

 

SP

07H

 

 

IP

40H(0 000000)

 

 

IE

40H(0 000000)

 

 

PCON

10H(000 0000)

 

 

PSW, DPH, DPL, A, B

 

 

 

SCON, TCON, TMOD

 

 

00H

T2CON, IOCON, TL0

 

 

TL1, TL2, TH0, TH1

 

 

 

TH2, RCAP2L, RCAP2H

 

 

 

P1, P2, P3

*0FFH(input port)

 

 

P0

*0FFH(floating)

 

 

SBUF

Undefined

 

INTERNAL RAM

 

 

 

ALE, PSEN

*“1” OUT

 

 

* Denotes direct resetting even if XTAL1·2 has stopped.

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Sonic Alert msm80154s, msm83c154s CPU internal status by reset, Denotes direct resetting even if XTAL1·2 has stopped