interface of rtc ht1380 with pic16f72

bharatwalia · Joined: 04 May 2009 Posts: 35 Location: India

Hi,
How to interface a RTC "ht1380" with pic16f72. Its a 8-PIN IC.

http://www.holtek.com.tw/pdf/consumer/1380_1v111.pdf

Pad Description
Pad No. Pad Name I/O
Internal
Connection
Description
1 X1 I CMOS 32768Hz crystal input pad
2 X2 O CMOS Oscillator output pad
3 VSS CMOS Negative power supply, ground
4 REST I CMOS Reset pin with serial transmission
5 I/O I/O CMOS Data input/output pin with serial transmission
6 SCLK I CMOS Serial clock pulse pin with serial transmission
7 VDD CMOS Positive power supply

Thanks

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

The Holtek HT1380 is similar to the DS1302. CCS has a driver for
the DS1302:

asmboy · Joined: 20 Nov 2007 Posts: 2128 Location: albany ny

is there a NAME for the goofy physical layer protocol these parts use ?

on first blush,
it it looks like vanilla SPI - but with a shared SDO/SDI line
is there a name for that ?

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Yes, it's called "3-wire" SPI.
http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#3-Wire_Serial_Buses