Excerpt from Ian's pages:

TrxAVR now supports a real time clock:

At present only supported for colour Tft displays
Displays UTC time and date and Local time and date
Clock setting from Hobcat - clock set in UTC
Local time offset can be set from Hobcat and also by a TrxAVR menu option.
Five I2C interfaced RTC chips supported:
ISL1220, DS3231, DS3232, PCF8563 and RTC-8564.

Ian has artwork available on the above web pages, for a small PCB to cater for various types of RTC chip, that are supported with this project.

Offered here, is an alternate PCB type that can fit over the back of the TftA PCB without any extra cabling. It "plugs in" to existing connectors on Tft, which are then replicated on my PCB. NOTE: this requires some extra space behind the Tft PCB. Check 1st before using this PCB. Check pictures below ! Also, a 'commercial' PCB is available with plated through holes etc.

Typical single sided PCB's pictured below. (click for larger size) There is NO 5v regulator on this home brew PCB, it uses the 5v from the Tft PCB. (Ian's PCB's have in-built regulator) The Pro PCB does have 5v regulator, to allow chassis fitting.

Above, is how the PCB is fitted to the TftA PCB. For other display types, chassis mount the PCB using the holes.
Pictures show an SMD type of battery but a CR2032 battery holder can also be fitted like Ian has done.

The homebrew PCB artwork has the copper as a cross-hatched area as I found this easier to home-brew using a laser printer. If you would prefer a solid copper type, please email me. vk3pe [qrz.com]

The PCB foils no longer available due to PC mafunction

The copper MUST be on the TOP of the PCB !

With a single sided PCB it's a bit tricky to fit the connectors. To fit the header pins on the top of the PCB it is best to use the type that the pins move easily in the plastic. Fit the header pins upside down with the pins just flush with the bottom of the PCB. Solder the pins quickly to the PCB pads to avoid damage to the plastic. Then, push the plastic down to the PCB with some pliers or similar.









Page last updated on February 2, 2016:- build info added

Page created on 9th Feb, 2011 by VK3PE

DS3231 or DS3232 or ISL1220 PCB


PCB Foils no longer available

Bill of Material

PCF8563 and RTC-8564 PCB


PCB Foils no longer available

Bill of Material

Pre-made PCB's ?

I have pre-ordered a small number of PCB's for the DS3231/32 & PCF8563. (any one of the RTC chips can be fitted to the PCB)

The PCB is in short supply. Email me to see if any available.

It is a double sided, plated through holes type PCB. For chassis mounting, the board can be cut to suit.

If anybody is interested, please email me. vk3peATbigpond.com (change AT to "@")

Above is the bare PCB from top and bottom.

Above is the ISL1220 version (note text for ISL1220 is in wrong place) If you use a SMD battery you need to insulate the area under the battery. NOT required for CR2032 battery holders.

Above is the RTC-8563 version. In both versions I fitted 78L05 not the SMD part. Note: trim cap is used.

Click pictures for larger view

Build information

Schematic pdf file (updated 25-03-11) Note, only one RTC chip is selected according to preference or availability. Refer to Ian's table of the various types for the differences.

Bill of Material (BOM Xcel file) updated 25-03-11, Note, you only need the parts to suit the RTC chip selected. See Schematic above also. NOT recommended to use the ISL1220 at present time.

Build hints and tips (Word file) NEW, 30th March 2011



If you are struggling for space, you might be able to fit right angled headers on the RTC PCB to reduce the height needs.

Otherwise, there are home brewable PCB's below.

A Real Time Clock (RTC) for PICaSTAR using the TFT display.

Ian, G3VPX, has full information on adding a RTC to your Trxavr PCB that also has a TFT colour display fitted.

CLICK HERE for Ian's RTC pages.