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CHAPTER 16 RESET FUNCTION
User’s Manual U15104EJ2V0UD
Table 16-1. Hardware Status After Reset (1/2)
Hardware
Status After Reset
Program counter (PC)
Note 1
Contents of reset
vector table (0000H,
0001H) are set.
Stack pointer (SP)
Undefined
Program status word (PSW)
Undefined
RAM
Data memory
Undefined
Note 2
General-purpose register
Undefined
Note 2
Port (output latch)
Ports 0, 1, 3 to 7, 12, 13 (P0, P1, P3 to P7, P12, P13)
00H
Port mode registers (PM0, PM3 to PM7, PM12)
FFH
Pull-up resistor option register 4 (PU4)
00H
Processor clock control register (PCC)
04H
Oscillation stabilization time select register (OSTS)
04H
DTS system clock select register (DTSCK)
00H
Note 3
Memory size switching register (IMS)
CFH
Note 4
Internal expansion RAM size switching register (IXS)
0CH
Note 5
8-bit timer/event counter
Counters 50 to 53 (TM50 to TM53)
00H
Compare registers 50 to 53 (CR50 to CR53)
Undefined
Clock select registers 50 to 53 (TCL50 to TCL53)
00H
Mode control registers 50 to 53 (TMC50 to TMC53)
00H
Watchdog timer
Clock select register (WDCS)
00H
Mode register (WDTM)
00H
Buzzer output controller
BEEP clock select register 0 (BEEPCL0)
00H
Clock output select register (CKS)
00H
Serial interface
Shift registers 30 to 32 (SIO30 to SIO32)
Undefined
Operating mode registers 30 to 32 (CSIM30 to CSIM32)
00H
Port select register 32 (SIO32SEL)
00H
Notes 1. During reset input or oscillation stabilization time wait, only the PC contents among the hardware
statuses become undefined. All other hardware statuses remain unchanged after reset.
2. The status before reset is retained even after reset in the standby mode.
3. Though the initial value is 00H, be sure to set it to 01H before use.
4. The initial value is CFH. Set the following value to this register depending on the model:
µ
PD178053:
C6H
µ
PD178054:
C8H
µ
PD178F054: Value corresponding to mask ROM versions
5. Do not assign a value other than 0CH.