M37754 Mitsubishi, M37754 Datasheet - Page 60

• Manufacturer Part Number: M37754
• Description: SINGLE-CHIP 16BIT CMOS MICROCOMPUTER
• Manufacturer: Mitsubishi

D-A CONVERTER
The D-A converter is an 8-bit R-2R method D-A converter and con-
sists of two independent D-A converters. Figure 72 shows the block
diagram of the D-A converter and Figure 73 shows the bit configura-
tion of A-D control register 1.
D-A conversion is performed by writing a value in the corresponding
D-A register. The conversion result is output by bits 6 and 7 of A-D
control register 1 (address 1F
result is output from DA
When bit 6 is “1”, the conversion result is output from DA
The output analog voltage V is determined according to the value n
(“n” is a decimal number) set in the D-A register.
V = V
The D-A output enable bit is cleared to “0” at reset. Whether to con-
nect the reference voltage input (V
depends on bit 5 of the A-D control register 1. The V
nected when bit 5 is “0” and is disconnected when bit 5 is “1” (High
impedance state).
Fig. 72 D-A converter block diagram
60
REF
V
REF
n/256 (n = 0 to 255)
V
select
REF
AV
connection
SS
0
pin.
V
REF
16
). When bit 7 is “1”, the conversion
: Reference voltage
REF
R-2R ladder network
) with the ladder network or not
D-A
0
pin
D-A
enable bit
0
REF
output
M37754M8C-XXXGP, M37754M8C-XXXHP
1
pin is con-
pin.
D-A register 0
(Address 68
Data bus (even)
16
)
AV
SS
When A-D or D-A conversion is not performed, current from the V
pin to the ladder network can be cut off by disconnecting ladder net-
work from the V
Before starting A-D or D-A conversion, wait for 1 s or more after
clearing bit 5 to “0”. An external buffer must be connected when con-
necting to a low impedance load because there is no built-in D-A out-
put buffer.
Fig. 73 A-D control register 1 bit configuration
Note : When the expansion function select bit (bit 5 of peripheral
M37754S4CGP, M37754S4CHP
7 6 5 4 3 2 1 0
function select register 1 ; refer to Fig. 62) is “1,” bit 5 can be
written and changed.
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
R-2R ladder network
REF
D-A
pin.
1
MITSUBISHI MICROCOMPUTERS
pin
D-A
enable bit
1
output
A-D control register 1
Not used for D-A converter
V
D-A
D-A
REF
0 : V
1 : V
0 : Disable output
1 : Enable output
0 : Disable output
1 : Enable output
1
0
D-A register 1
(Address 6A
output enable bit
output enable bit
connection select bit (Note)
REF
REF
is connected
is not connected
16
)
Address
1F
16
REF