EM78P257
OTP ROM
want to be restarted , we must disable IR in advance and then enable IR again.The time delay
between two pulse trains is determined by software.
3. Pin Description
SYMBOL
PIN
DESCRIPTION
P60 to P66
P50 to P57
7~13
Standard I/O Port lines, generally used for keypad scanning
1~4,17~20 Standard I/O Port lines, generally used for keypad sensing
P67(IR OUT)
OSCO
OSCI
14
16
17
15
6
Pulse train output pin, capable of sinking 30mA
External clock signal input
External clock signal input
Power supply
Vdd
Vss
Ground
4. Programmed the Related Registers
When defining IR mode is defined, refer to the related register of its operation as shown in the Table 27 and Table
28 below.
Table 27 Related Control Registers of the IR Mode
Address
0x0B
0x08 TCCCR/IOC80 TCC2E
0x0D IRCR/RD DP1/0
Name
Bit 7
0
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit1
Bit 0
TCR(2)/RB
TCCBIE/0 TCCBTS/0 TCCBTE/0
TCC4E
DP0/0
0
-
TCCCIE/0 TCCCTS/0 TCCCTE/0
TCC6E
MF1/0
TCCBE
MF0/0
-
-
-
IRE/0
HF/0
LGP/0
PWM/0
<Note> *Bit name/initial value
Table 28 Related status/data register of the IR mode
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit1
Bit 0
0x06
0x07
0x09
0x0A
0X0B
TCCBL/IOC61 TCCBL7 TCCBL6 TCCBL5 TCCBL4 TCCBL3 TCCBL2 TCCBL1 TCCBL0
TCCBH/IOC71 TCCBH7 TCCBH6 TCCBH5 TCCBH4 TCCBH3 TCCBH2 TCCBH1 TCCBH0
LTR/IOC91
HTR/IOCA1
PTR/IOCB1
LTR7
HTR7
PTR7
LTR6
HTR6
PTR6
LTR5
HTR5
PTR5
LTR4
HTR4
PTR4
LTR3
HTR3
PTR3
LTR2
HTR2
PTR2
LTR1
HTR1
PTR1
LTR0
HTR0
PTR0
• TCCBL : An eight-bit clock counter is for the least significant byte of TCCBX. TCCBL, which can be
read, written, and cleared at any reset condition.
• TCCBH : An eight-bit clock counter is for the most significant byte of TCCBX. TCCBH, which can be
read, written, and cleared at any reset condition.
• Low-time Register :The 8-bit Low-time register that controls the active or Low period of the pulse. The
High-time register controls the inactive or High period of the cycle.
• The decimal value of its contents determines the number of oscillator cycles indicating that the IR
OUT pin is active. The active period of IR OUT can be calculated as follow:
tLow=(decimal value held in Low-time register)/fosco
• High-time Register :The 8-bit High-time register control the inactive or High period of the pulse.
This specification is subject to change without prior notice.
62
07.27.2004 (V1.4)
ELAN [ ELAN MICROELECTRONICS CORP ]
