m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 54

• Manufacturer Part Number: m3819
• Description: Mitsubishi 8-bit Single-chip Microcomputer 740 Family / 38000 Series
• Manufacturer: Renesas Electronics Corporation.

Fig. 34 FLDC timing
40
Timing Setting
The digit time (T
(address 0037
can be set with the FLDC mode register 1 (address 0036
Note that flickering will occur if the repetition frequency (1/
(T
digit timing T
FLD Automatic Display Start
To perform FLD automatic display, set the following registers.
Automatic display mode is selected by writing “1” to the bit 0 of
the FLDC mode register 2 (address 0037
matic display is started by writing “1” to the bit 1.
• Port P0 segment/digit switch register
• Port P2 digit/port switch register
• Port P8 segment/port switch register
• Port PA segment/port switch register
• FLDC mode register 1
• FLDC mode register 2
• FLD data pointer
disp
number of digits + T
G n
G n-1
G n-2
G 1
Segment
output
disp
16
.
disp
). The T
Segment
FLD digit interrupt occurs
at the rising edge of each digit
) can be set with the FLDC mode register 2
Digit
scan
scan
and digit/segment OFF time (T
T
disp
)) is an integral multiple of the
T
off
16
), and the auto-
T
disp
16
off
).
)
During automatic display bit 1 of the FLDC mode register 2 al-
ways keeps “1”, automatic display can be interrupted by writing
“0” to the bit 1.
Key-scan
If key-scan is performed with the segment during the key-scan
blanking period T
1. Write “0” to the bit 0 (automatic display control bit) of the
2. Set the port corresponding to the segment for key-scan to
3. Perform the key-scan.
4. After the key-scan is performed, write “1” (automatic display
Note on performance of key-scan in the above 1 to 4 sequence.
1. Do not write “0” to the bit 1 of FLDC mode register 2 (ad-
2. Do not write “1” to the port corresponding to the digit.
FLDC mode register 2 (address 0037
the output port.
mode) to the bit 0 of FLDC mode register 2 (address
0037
dress 0037
FLD blanking interrupt occurs
at the falling edge of the last digit
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
16
).
Segment setting by software
16
).
T
scan
scan
MITSUBISHI MICROCOMPUTERS
, take the following sequence:
3819 Group
16
).