MC68HC68T1 Datasheet, PDF (17/26 Pages) Motorola, Inc – Real-Time Clock plus RAM with Serial Interface

SS
CPOL = 1*
SCK
SHIFT
INTERNAL
STROBE
SS
CPOL = 0*
SCK
SHIFT
INTERNAL
STROBE
MOSI
MSB
MSB–1
* CPOL is a bit that is set in the microcomputer’s Control Register.
Figure 13. Serial Clock (SCK) as a Function of MCU Clock Polarity (CPOL)
SS
SCK*
MOSI
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
A7
MSB
A6
A5
A4
A3
A2
A1
* SCK can be either polarity.
Figure 14. Address Byte Transfer Waveforms
A0
LSB
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
SS
ÎÎ SCK*
ÎÎ_MSB
ÎÎ _MOSI
D7
ÎÎÎÎ_MSB
ÎÎÎÎ _MISO
D7
D6
D6
D5
D5
D4
D4
D3
D3
D2
D2
D1
D1
LSB
D0
LSB
D0
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
* SCK can be either polarity.
Figure 15. Read/Write Data Transfer Waveforms
MOTOROLA
MC68HC68T1
17