sh6614 SinoWealth Micro-Electronics Corp. Ltd, sh6614 Datasheet - Page 11

• Manufacturer Part Number: sh6614
• Description: 4k 4-bit Microcontroller With Lcd Driver
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

7.2. Controlling the pull-up MOS
PORTA, PORTB contain pull-up MOS controlled by program. Bit3 of the PMOD register controls the on/off of all pull-up MOS
simultaneously. Pull-up MOS are also controlled by the port data registers (PA, PB) of each port as well. Thus the pull-up MOS
can be turned on/off.
7.3. Port Interrupt
PORTB interrupt (falling edge) is not controlled by the Port I/O register. This means that if a interrupt request (IEx is set to 1 &
one port bit high goes low) has been touched therefore the condition is the other port bits are high level whenever the port bit is
output or input.
7.4. External
PortA.0 is shared by external interrupts (active low).
7.5. Port I/O control register:
I/O control register: PACR.X, PBCR.X (X = 0, 1, 2, 3)
1: Use as an output buffer.
0: Use as an input buffer (initial power-on).
7.6. Port mode register (PMOD)
PAM1, PAM2:
HLM:
PPULL:
7.7. Heavy load mode (HLM)
The MCU has a heavy load protection circuit for when the battery load becomes heavy, such as, when an external buzzer
sounds or an external speaker is turned on. In this mode, the crystal oscillator circuit has been backup for high gain. When setup
this mode, more power would be provided to an oscillator circuit. Unless it is nessary, be careful not to set this mode with the
software since the mode enter would delay for one instruction. Please activate heavy load driving only after setting HLM at least
one instruction wait cycle through the software. The following shows the programming setting.
Address
$13
Address
$0B
$0C
HLM: 0 = Heavy load protection mode is released
INT
PPULL
1 = Heavy load protection mode is set.
Bit3
0
Please see the PSG
Enable heavy load mode 0: Disable
Port pull-up MOS
PAM2
PACR.3
PBCR.3
Bit2
HEAVYLOAD
Bit3
HLM
PAM1
Bit1
0: Disable pull-up MOS
OFF
ON
0
1
PACR.2
PBCR.2
HLM
Bit0
Bit2
Bit1, 2:Select PA.1, PA.2 as I/O port or PSG output
Bit0:Hevey load mode
Bit3:Port pull-up control
1 Instruction Cycle Time
11
PACR.1
PBCR.1
Bit1
1: Enable
1: Enable pull-up MOS
Function
PACR.0
PBCR.0
Bit0
SH6614/B/C
R/W