t6020m ATMEL Corporation, t6020m Datasheet - Page 43

• Manufacturer Part Number: t6020m
• Description: Low-current Microcontroller For Watchdog Function
• Manufacturer: ATMEL Corporation

Due to the byte-orientated data control, the SSI when
running normally generates serial bit streams which are
submultiples of 8 bits. An SSI output masking (OMSK)
function permits, however, the generation of bit streams
of any length. The OMSK signal is derived indirectly
from the 4-bit prescaler of the Timer 2 and masks out a
programmable number of unrequired trailing data bits
during the shifting out of the final data word in the bit
stream. The number of non-masked data bits is defined by
Rev. A3, 02-Apr-01
T1OUT
SYSCL
POUT
TOG2
SCL
/2
SC
CL2/1
Shift_CL
4-bit counter 2/1
Figure 48. SSI output masking function
Compare 2/1
SO
CM1
MSB
Timer 2
SSI-control
8-bit shift register
the value pre-programmed in the prescaler compare
register. To use output masking, the modulator stop mode
bit (MSM) must be set to ’0’ before programming the
final data word into the SSI transmit buffer. This in turn,
enables shift clocks to the prescaler when this final word
is shifted out. On reaching the compare value, the
prescaler triggers the OMSK signal and all following data
bits are blanked.
LSB
Control
OMSK
SI
T6020M
Output
SO
13834
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