Sharp MZ-5500 - Page 82

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171 OSCOUT
IS' ALARM
Fig.13-2 RPSCOl . pin configuration
°The RPSCOI generates clock pulse internally by connecting th e 32.768KHz
ceramic oscillator and the CR network between OSCIN and OSCOUT, and
divides it for the counter operation.
°The CS pin detects a power down, and then sets the circuit to
the power down condition. When power is on to the personal computer, Tri
and Tt2 in Fig.2-l3-1 are active so that +SV is supplied to the RPSCOi and
the backup battery is being recharged. When power is off, it makes Tri
gone inactive f~rst, then Tr2. This isolates the circuit on the right of
Tr2. Then the backup battery supplies power to the RP5COI, which kee ps th p
. time along with the internal RAH.
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