saa5288 NXP Semiconductors, saa5288 Datasheet - Page 10

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

Philips Semiconductors
7.3.6
One 14-bit DAC is available to allow direct control of analogue sections of the television. The 14-bit PWM is controlled
using Special Function Registers TDACL and TDACH.
The output of the TPWM is a pulse of period 42.66 s. The 7 most significant bits, TDACH.TD13 (MSB) to TDACH.TD8
and TDACL.TD7, alter the pulse width between 0 and 42.33 s, in much the same way as in the 6-bit PWMs. The 7 least
significant bits, TDACL.TD6 to TDACL.TD0 (LSB), extend certain pulses by a further 0.33 s, e.g. if the 7 least significant
bits are given the value 01H, then 1 in 128 cycles is extended. If the 7 least significant bits are given the value 02H, then
2 in 128 cycles is extended, and so forth.
The TPWM will not start to output a new value until after writing a value to TDACH. Therefore, if the value is to be
changed, TDACL should be written to before TDACH.
7.3.6.1
Table 5 TPWM High Byte Register (SFR address D3H)
Table 6 Description of TDACH bits
7.3.6.2
Table 7 TPWM Low Byte Register (SFR address D2H)
Table 8 Description of TDACL bits
1997 Jun 24
TV microcontroller with full screen
On Screen Display (OSD)
6 to 0
PWE
TD7
BIT
BIT
7
7
6
5
4
3
2
1
0
7
7
14-
TPWM High Byte Register (TDACH)
TPWM Low Byte Register (TDACL)
BIT
PWM DAC
TD6 to TD0
SYMBOL
SYMBOL
TD13
TD12
TD10
TD11
PWE
TD9
TD8
TD6
TD7
6
6
If PWE is set to a logic 1, the TPWM is active and controls port line P2.0. If PWE is set
to a logic 0, the port pin is controlled by the corresponding bit in the port SFR.
not used
These 6-bits along with bit TD7 in the TDACL register control the pulse width period.
TD13 is the most significant bit.
This bit is used with bits TD13 to TD8 in the TDACH register to control the pulse width
period.
These 7-bits extend certain pulses by a further 0.33 s.
TD13
TD5
5
5
TD12
TD4
4
4
10
TD11
TD3
3
3
DESCRIPTION
DESCRIPTION
TD10
TD2
2
2
Preliminary specification
TD9
TD1
1
1
SAA5288
TD8
TD0
0
0