saa5290ps NXP Semiconductors, saa5290ps Datasheet - Page 13

• Manufacturer Part Number: saa5290ps
• Description: Economy Teletext And Tv Microcontrollers
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.3.6
One 14-bit DAC is available to allow direct control of
analog 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.
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
1998 Dec 14
Economy teletext and TV microcontrollers
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
13
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.
TD11
TD3
3
3
DESCRIPTION
DESCRIPTION
TD10
TD2
2
2
SAA5x9x family
Preliminary specification
TD9
TD1
1
1
TD8
TD0
0
0