m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 146

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

2. APPLICATION
Fig. 2.5.31 Control procedure [FLD display by software]
132
Control procedure :
Figure 2.5.31 shows a control procedure.
Wait until the
“H” level output
of port P3 is
stabilized.
N
FLDM1
FLDM2
P2D
P0
P1
P3
Initialization
Push register to stack etc.
Renew data table pointer for Key-scan
Timer 1 interrupt processing routine
Transfer the contents of port P2
(Address:04
(Address:00
(Address:02
(Address:06
Complete to display all digits?
Set data table for Key-scan
to port P3 (Address:06
(Address:36
(Address:37
(Address:05
Complete Key-scan?
Wait for Key-scan
16
16
16
16
RESET
) to Work RAM
)
), bit0–bit3
)
~ ~
~ ~
RTI
16
16
16
Y
Y
), bit7
), bit1, bit0
)
3819 Group USER’S MANUAL
16
00000000
)
00
0000
00
00
1
16
16
2
2
2
N
P0 (Address:00
P3 (Address:06
P0 (Address:00
P1 (Address:02
Set the bits 7 to 4 of the Port P2 direction
register used for the Key-scan to the input
mode.
Segment key-scan
FLD display : OFF
Read keys.
(Set the Port P2 direction register (P2D)
(Address:05
initialization.)
16
16
16
16
16
), bit0, bit1
)
),bit2–bit7
),bit0–bit3
) to the input mode in the
~ ~
2.5 FLD controller
MITSUBISHI MICROCOMPUTER
segment
data
digit
data
3819 Group