UPSD3354DV-40U6 Datasheet, PDF (139/272 Pages) STMicroelectronics – fast 8032 MCU with programmable logic

UPSD33xx
I²C interface
Is this the next to last byte to receive from Slave?
If this is the next to last byte, do not allow Master to ACK on
next interrupt.
● S1CON.AA = 0, don’t let Master return ACK
● Exit ISR, now ready to recv last byte from Slv
If this is not next to last byte, let Master send ACK to Slave
<S1CON.AA is already 1>
● Exit ISR, ready to recv more bytes from Slave
Else If mode is Slave-Transmitter
Is this Intr from SIOE detecting a STOP on bus?
If Yes, a STOP was detected:
● S1DAT = dummy, write to release bus
● Exit ISR, Master needs no more data bytes
If No, a STOP was not detected, continue:
) _{ACK recvd from Master? (status.ACK_RESP=0?)}
t(s ^{If No, an ACK was not received:}
c _{● S1DAT = dummy, write to release bus}
du ● Exit ISR, Master needs no more data bytes
ro If Yes, ACK was received, then continue:
P _{● S1DAT = xmit_buf[buffer_index], transmit byte}
te ^{● Exit ISR, transmit next byte on next interrupt}
le _{Else If mode is Slave-Receiver:}
so _{Is this Intr from SIOE detecting a STOP on bus?}
b _{If Yes, a STOP was detected:}
- ^O ● recv_buf[buffer_index] = S1DAT, get last byte
) _{● Exit ISR, Master has sent last byte}
t(s If No, a STOP was not detected, continue:
uc Determine if this Interrupt is from receiving an address or a data
d _{byte from a Master.}
ro _{Is (S1CON.ADDR = 1 and S1CON.AA =1)?}
P _{If No, intr is from receiving data, goto C:}
te_{If Yes, intr is from an address, continue:}
le_{● slave_is_adressed = 1, local variable set true}
so _{<indicates Master selected this slave>}
Ob ^{● S1CON.ADDR = 0, clear address match flag}
Determine if R/W bit indicates transmit or receive.
Doc ID 9685 Rev 7
139/272