saa5288 NXP Semiconductors, saa5288 Datasheet - Page 11

• Manufacturer Part Number: saa5288
• Description: Microcontroller With Full Screen Screen Display
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.3.7
Up to 4 successive approximation ADCs can be
implemented in software by making use of the on-chip 8-bit
DAC and multiplexed voltage comparator. The software
ADC uses 4 analog inputs which are multiplexed with P3.0
to P3.3.
Table 9 ADC input channel selection
1997 Jun 24
TV microcontroller with full screen
On Screen Display (OSD)
CH1
S
0
0
1
1
OFTWARE
ADC
CH0
0
1
0
1
handbook, halfpage
P3.0
P3.1
P3.2
P3.3
INPUT PIN
P3.3/ADC3
P3.0/ADC0
P3.1/ADC1
P3.2/ADC2
MULTIPLEXER
CH1, CH0
Fig.3 SAD block diagram.
REF
11
SAD7 to SAD0
8-BIT DAC
The control of the ADC is achieved using the Special
Function Registers SAD and SADB.
SAD.CH1 and SAD.CH0 select one of the four inputs to
pass to the comparator. The other comparator input
comes from the DAC, whose value is set by SAD.SAD7
(MSB) to SAD.SAD4 and SADB.SAD3 to SADB.SAD0
(LSB). The setting of the value SAD.SAD7 to SAD.SAD4
must be performed at least 1 instruction cycle before the
setting of SAD.ST to ensure comparison is made using the
correct SAD.SAD7 to SAD.SAD4 value.
The output of the comparator is SAD.VHI, and is valid after
1 instruction cycle following the setting of SAD.ST to
logic 1.
ST
REF
C1
1D
MGL115
VH1
Preliminary specification
SAA5288