M16C/62P Group (M16C/62P, M16C/62PT)
7. Processor Mode
Rev.2.41
Jan 10, 2006
Page 56 of 390
REJ09B0185-0241
Figure 7.1
PM0 Register
Processor Mode Register 0
(1)
Symbol
Address
After Reset
PM0
0004h
00000000b (CNVSS pin = L)
00000011b (CNVSS pin = H)
Bit Symbol
Bit Name
Function
RW
0 : RD
___
, BHE
_____
, WR
____
1 : RD
___
, WRH
______
, WRL
_____
b5 b4
0 0 : Multiplexed bus is unused
(Separate bus in the entire CS
___
space)
0 1 : Allocated to CS2
_____
space
1 0 : Allocated to CS1
_____
space
1 1 : Allocated to the entire CS
___
space
(3)
NOTES :
1.
2.
3.
4.
RW
PM06
PM00
RW
PM02
R/W Mode Select Bit
(2)
RW
PM01
RW
RW
b7 b6 b5 b4
RW
RW
b3 b2 b1 b0
b1 b0
0 0 : Single-chip mode
0 1 : Memory expansion mode
1 0 : Do not set
1 1 : Microprocessor mode
Processor Mode Bit
(4)
Multiplexed Bus Space Select
Bit
(2)
0 : Address output
1 : Port function (Address is not output)
Port P4_0 to P4_3 Function
Select Bit
(2)
Write to this register after setting the PRC1 bit in the PRCR register to “1” (w rite enable).
RW
Setting this bit to “1” resets the microcomputer.
When read, its content is “0”.
Softw are Reset Bit
PM03
0 : BCLK is output
1 : BCLK is not output (Pin is left high-impedance)
BCLK Output Disable Bit
(2)
PM07
PM04
PM05
To set the PM01 to PM00 bits are “01b” and the PM05 to PM04 bits are “11b” (multiplexed bus assigned to the entire
Effective w hen the PM01 to PM00 bits are set to “01b” (memory expansion mode) or “11b” (microprocessor mode).
The PM01 to PM00 bits do not change at softw are reset, w atchdog timer reset and oscillation stop detection reset.
CS
___
space), apply an “H” signal to the BYTE pin (external data bus is 8 bits w ide). While the CNVSS pin is held “H”
(= VCC1), do not rew rite the PM05 to PM04 bits to “11b” after reset.
If the PM05 to PM04 bits are set to “11b” during memory expansion mode, P3_1 to P3_7 and P4_0 to P4_3 become
I/O ports, in w hich case the accessible area for each CS
___
is 256 bytes.
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