CPU (LSI1: GT913F)
The 16-bit CPU contains a 1k-byte RAM, three 8-bit I/O ports, two timers, a key controller and serial interfaces.
The CPU detects key velocity by counting the time between first-key input signal FI and second-key SI from
the keyboard. The CPU reads sound data and velocity data from the sound source ROM in accordance with
the selected tone; the CPU can read rhythm data simultaneously when a rhythm pattern is selected. Then the
CPU provides 16-bit serial sound data to the DSP. The CPU also controls MIDI input/output and stores
sequencer data into the working storage RAM.
The following table shows the pin functions of LSI1.
Plin No.Tterm inaInn/O uFunctio
10TtXDOduNotuse
20RnXDIdNotuse
30StCKOtuAPO (Auto PowerO ff)signaloutpu
41TtXDOtuM IDIsignaloutpu
51RnXDItM IDIsignalinpu
61StCKOtu1 M HZ synchronizing pulse outpu
7CAnVCIeDVDD (+5 V)sourc
AC adaptordetection term inal.
+5 V when the keyboard is powered by batteries and
80AnNI
becom es 0 V to cancelthe APO function when AC
adaptoris connected.
91ANNNotused.Connected to ground.
1D0AnG NIeG round (0 V)sourc
1K1BtCOtuBitclock outpu
1O2StOtuSerialsound data outpu
1K3LtRCOtuW ord clock outpu
1D4GnNIeG round (0 V)sourc
115,16XtLT0,XLTItn/O u30 M Hz clock input/outpu
1C7VnCIe+5 V sourc
118,19MnD0,M DIlM ode selection term ina
2B0RnSTItResetsignalinpu
2I1NnMItPowerO N signalinpu
202ItNT/P1Irn/O uData bus forthe LCD drive
FI0 ~ FI3
23 ~ 30IlnTerm inalforkey inputsigna
SI0 ~ SI3
371 ~ 38KtC0 ~ KCOluTerm inalforkey scan signa
FI4 ~ FI7
39 ~ 46IlnTerm inalforkey inputsigna
SI4 ~ SI7
487,48FNI8,SINotused
499FnIIlTerm inalforbutton inputsigna
590SnIIrData bus forLCD drive
501FnI1IlTerm inalforbutton inputsigna
532StI10/P2OruData bus forthe LCD drive
523 ~ 55KnI0 ~ KIIlTerm inalforbutton inputsigna
5B6MtW NOPuW rite enable signalforthe DS
N 7 N |
ACEC
