The new 16 k memory-card

This card was launched in 1984. The card is a dubbel-sided print. The components are indicated by means of a silkscreen print. Expanding the memory was an important objective. Loading programs again and again from a tape recorder on 300 baud was tedious. Keeping your data under write-protect in Ram was a relief.

Battery Backup

Pin 24 from all memory ICs is connected to the battery back-up circuit. When the Atom is connected to the power supply it starts feeding these ICs. However, when the Atom is switched off and a battery is mounted ± 2,6 volt is sufficient to secure the contents of the chips.

The layout.

images/16k-nwe.gif

The Components.

IC’sresistorscapacitors
IC 1-86116 R122KOhmC1-C12100nF mkm
IC 974LS245R233KOhmC1310 mF  tantaal
IC 10-IC 1174LS244R3 22 KOhm
IC 1274LS132R4470OhmDiode D1 led
IC 1374LS01R5 56OhmD2 OA95
IC 1474LS01R6-R1533KOhmD3 1N4001
IC 15-IC 164071R16-R33 33KOhm
IC 974LS10Transistor T BC547B

Write Protect

The ICs 6, 7 and 8 are on the print already part of the Write Protect circuit. Pin 21 from these ICs is connected to switch number 6 from the dipswitch device. The pins 21 from ICs 1 until 5 may be connected to the dipswitches 1 t/m 5. There are "islands" available for that purpose. If a FDC for the Atom was available for a modest price, there would probably be hardly any necessity for WP anymore.
images/home.gif
images/terug.gif