IC-6 is the static RAM chip that holds the band, frequency,mode, memories for long term storage.  It is used particularly when the radio is turned off in order to keep track of where you were operating.  When the rig is turned back on, data is read from the ram chip and the radio is set up in the last known state before it was turned off.

uPD5101 Ram Chip pinouts

uPD5101 Spec Sheet

Address Pins

Pin 1: Address bit A3

Pin 1: A3

 

Pin 2: Address Bit A2

Pin 2: A2

 

Pin 3: Address Bit A1

Pin 3: A1

 

Pin 4: Address Bit A0

Pin 4: A0

 

Pin 5: Address Bit A5

Pin 5: A5

 

Pin 6: Address Bit A6

Pin 6: A6

 

Pin 7: Address Bit A7

Pin 7: A7

 

Pin 21: Address Bit A4

Pin 21: A4

 

Ground Pin

Pin 8: Ground

Pin 8: GND

 

Data Input/Output Pins 9 -16

Pin 9: Data In 0

Pin 9: DI 0

 

Pin 10: Data Output 0

Pin 10: DO 0

 

Pin 11: Data Input 1

Pin 11: DI 1

 

Pin 12: Data Output 1

Pin 12: DO 1

 

Pin 13: Data Input 2

Pin 13: DI 2

 

Pin 14: Data Output 2

Pin 14: DO 2

 

Pin 15: Data Input 3

Pin 15: DI 3

 

Pin 16: Data Output 3

Pin 16: DO 3

 

Chip Enable Pins 17, 19

Pin 17: Chip Enable 2 (High Active)

Pin 17: CE2

 

Pin 19: Chip Enable 1 (Low Active)

Pin 19: CE1 (low active)

 

Output Disable

Pin 18: Output Disable – Keeps the Ram from putting it’s data on the shared output lines.

Pin 18: OD

 

Read/Write

Pin 20: Read/Write – Selects Read or Write mode

Pin 20: RW

VCC

Pin 22: +5 volts VCC

Pin 22: VCC