@ All of our latest clocks now use a different circuit chip that will allow the RTC to support 32K of battery-backed-up RAM. There are some minor changes which must be made to accommodate the new chip style.
@ CHANGES FOR TYPE 'E' CIRCUITS:
Type 'E' chips have a green letter 'E' inside the upper surface. Circuits with a letter 'B' on the top surface are type 'B' circuits, for which these changes do not apply.
All type 'E' clocks use the programs; RTC RD(E) to read the clock, and RTC WRT(E) to set the clock . These are the programs with the 'wristwatch' logo.
The circuit changes listed below are only needed for those who are building RTC kits, or installing clocks internally. Otherwise, there are no differences in the use of the clock.
The changes are:
1) The wire that is to be soldered to position number 27 on the 'B' chip are must be soldered to position number 8 on the 'E' chips.
2) The pins at positions 10 and 11 must be soldered together on the 'E' chips. On both 'E' and 'B' chip, the pin at position 11 is soldered to the joystick 'D' plug position 1.
@TYPE 'E' Changes
@ On this circuit diagram, the numbers inside the rectange representing the type 'E' RTC circuit refer to the pin positions for the joystic port#2: if you are unfamiliar with the joystick port pin positions, please refer to your Commodore 64, or 128 Reference Guide.
On the diagram, the numbers along the bottom and top of the rectangle representing the type 'E' circuit refer to the standard 28-pin numbering system for integrated circuits. The numers show the positions as viewed with the bottom of the chip facing you.
The only deviations from the Type 'B' assembly instructions are shown by the '+' and the 'X'.
The wire from the joystick port pin#2, that the 'B' instructions tell you to connect to the chip pin position #27 ( shown by a 'plus' ) must instead be connected to the chip pin position number 8.
The chip pin positions number 10 and number 11 must be connected to each other, by bending the pins so they touch, then soldering, or by soldering the pins together with a short wire. The 'X' indicates this change from the 'B' instructions. Note that the joystick port pin position number 1 is soldered to pin number 11 in both the 'E', and 'B' circuits.
These two changes, plus the use of the 'E' read and write programs, are the only changes necessary.
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