Electronics; Central Processing Unit - Ericsson EF738 Service Manual

Accessories

Electronics

The electronics of the MC7000 is designed around the Central Processing Unit.

Central Processing Unit

The Central Processing Unit (CPU) is equipped with 4kbyte ROM, thus making it
possible to control the entire MC7000 charger.
The supply voltage to the CPU is +3.8V which is being derived from a linear volt-
age regulator and a crystal generates a 5MHz clock frequency to the oscillator input
of the CPU.
The Central Processing Unit interacts with the following major peripheral blocks:
• Supply Current Monitor
• Charge Switches; front & rear
• Voltage Monitors; front & rear
• Phone On/Off Status
• Discharger
• LED Indicators; front & rear
• Temperature Guard
ACCDCIO
18
System
Bus
Connector
Supply
Current
Monitor
Temp
Guard
CPU
Front
LEDs
Rear
LEDs
Front
Charge
Switch
Front
Voltage
Monitor
Rear
Charge
Switch
Rear
Voltage
Monitor
Phone
On/Off
Status
Front
Slot
DCIO
VDD
Rear
Slot
+V
Dis-
charger