HT46C23 datasheet(25/48 Pages) HOLTEK

25 / 48 page

HT46R23/HT46C23

Rev. 1.60

May 3, 2004

Receive Acknowledge Bit

When the receiver wants to continue to receive the next data byte, it generates an acknowledge bit (TXAK) at the 9th

clock. The transmitter checks the acknowledge bit (RXAK) to continue to write data to the I

2C Bus or change to receive

mode and dummy read the HDR register to release the SDA line and the master sends the STOP signal.

Options

The following table shows all kinds of options in the microcontroller. All of the options must be defined to ensure proper

system function.

No.

Options

OSC type selection.

This option is to decide if an RC or crystal oscillator is chosen as system clock.

WDT source selection.

There are three types of selection: on-chip RC oscillator, instruction clock or disable the WDT.

CLRWDT times selection.

This option defines how to clear the WDT by instruction.

²One time² means that the CLR WDT instruction can

clear the WDT.

²Two times² means only if both of the CLR WDT1 and CLR WDT2 instructions have been exe-

cuted, then WDT can be cleared.

Wake-up selection.

This option defines the wake-up function activity. External I/O pins (PA only) all have the capability to wake-up

the chip from a HALT.

Pull-high selection.

This option is to decide whether a pull-high resistance is visible or not in the input mode of the I/O ports.

PA0~PA7, can be independently selected.

PFD selection:

PA3: level output or PFD output

PWM selection: (7+1) or (6+2) mode

PD0: level output or PWM0 output

PD1: level output or PWM1 output

WDT time-out period selection.

There are four types of selection: WDT clock source divided by 2

12,213,214 and 215

Low voltage reset selection: Enable or disable LVR function.

2C Bus selection:

PA6 and PA7: I/O or I

2C Bus function

HT46C23 Datasheet(PDF) 25 Page - Holtek Semiconductor Inc