deveopmen
Rev.B2 for proof reading
Usage precaution
Mitsubishi Microcomputers
M32C/83 group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
341
Example) When DMA request cause is changed to timer A0 and using DMA0 in single transfer
after DMA initial setting
push.w
R0
; Store R0 register
stc
DMD0, R0
; Read DMA mode register 0
and.b
#11111100b, R0L
; Clear DMA0 transfer mode select bit to "00"
ldc
R0, DMD0
;
DMA0 disabled
mov.b
#10000011b, DM0SL
;
Select timer A0
;
(Write "1" to DMA request bit simultaneously)
nop
:
ldc
R0, DMD0
;
DMA0 enabled
pop.wR0
; Restore R0 register
Noise
(1) A bypass capacitor should be inserted between Vcc-Vss line for reducing noise and latch-up
Connect a bypass capacitor (approx. 0.1
μ
F) between the Vcc and Vss pins using short wiring and
thicker circuit traces.
Precautions for using CLK
OUT
pin
When using the Clock Output function of P5
3
/CLK
OUT
pin (f
8
, f
32
or fc output) in single chip mode, use
port P5
7
as an input only port (port P5
7
direction register is "0").
Although port P5
7
may be set as an output port (port P5
7
direction register is "1"), it will become high
impedance and will not output "H" or "L" levels.
HOLD signal
When using the HOLD input while P4
0
to P4
7
and P5
0
to P5
2
are set as output ports in single-chip mode,
you must first set all pins for P4
0
to P4
7
and P5
0
to P5
2
as input ports, then shift to microprocessor mode
or memory expansion mode.
Reducing power consumption
(1) When A-D conversion is not performed, select the Vref not connected with the Vref connect bit of A-D
control register 1. When A-D conversion is performed, start the A-D conversion at least 1
μ
s or longer
after connecting Vref.
(2) When using AN
4
(P10
4
) to AN
7
(P10
7
), select the input disable of the key input interrupt signal with the
key input interrupt disable bit of the function select register C .
When selecting the input disable of the key input interrupt signal, the key input interrupt cannot be
used. Also, the port cannot be input even if the direction register of P10
4
to P10
7
is set to input (the
input result becomes undefined). When the input disable of the key input interrupt signal is selected,
use all AN
4
to AN
7
as A-D inputs.
(3) When ANEX0 and ANEX1 are used, select the input peripheral function disable with port P9
5
and P9
6
input peripheral function select bit of the function select register B3.
When the input peripheral function disable is selected, the port cannot be input even if the port direc-
tion register is set to input (the input result becomes undefined).
Also, it is not possible to input a peripheral function except ANEX0 and ANEX1.
At least 8 + 6 x N cycles
(N: enabled channel number)