PD16311
Key Matrix and Key-Input Data Storage RAM
The key matrix is of 12
4 configuration, as shown below.
KEY
1
KEY
2
KEY
3
KEY
4
Seg
10
/KS
10
Seg
11
/KS
11
The data of each key is stored as illustrated below, and is read by a read command, starting from the least
significant bit.
KEY
1
…KEY
4
Seg
1
/KS
1
Seg
3
/KS
3
Seg
5
/KS
5
Seg
7
/KS
7
Seg
9
/KS
9
Seg
11
/KS
11
b0------------ b3
KEY
1
…KEY
4
Seg
2
/KS
2
Seg
4
/KS
4
Seg
6
/KS
6
Seg
8
/KS
8
Seg
10
/KS
10
Seg
12
/KS
12
b4 ------------b7
Reading sequence
When the most significant bit of data (Seg
12
b
7
) has been read, the least significant bit of the next data (Seg
1
b
0
) is
read.
LED Port
Data is written to the LED port by a write command, starting from the least significant bit of the port. When a bit of
this port is 0, the corresponding LED lights; when the bit is 1, the LED goes off. The data of bits 6 through 8 is
ignored.
MSB
−
−
−
b4
b3
b2
b1
LSB
b0
LED1
Don't care
LED2
LED3
LED4
LED5
On power application, all the LEDs remain dark.
6
Seg
12
/KS
12
Seg
1
/KS
1
Seg
2
/KS
2
Seg
3
/KS
3
Seg
4
/KS
4
Seg
5
/KS
5
Seg
6
/KS
6
Seg
7
/KS
7
Seg
8
/KS
8
Seg
9
/KS
9
NEC [ NEC ]
