saa5290ps NXP Semiconductors, saa5290ps Datasheet - Page 12

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

Philips Semiconductors
7.3.5
Eight 6-bit DACs are available to allow direct control of analog parts of the television.
Each low resolution 6-bit DAC is controlled by its associated Special Function Register (PWM0 to PWM7). The PWM
outputs are alternative functions of Port 2 and Port 3.4. The PWE bit in the SFR for the port corresponding to the PWM
output should be set to logic 1 for correct operation of the PWM output, e.g. if PWM0 is to be used, P2.1 should be set
to logic 1 setting the port pin to high-impedance.
7.3.5.1
Table 3 Pulse Width Modulator Registers (see Table 10 for addresses)
Table 4 Description of PWMn bits (n = 0 to 7)
1998 Dec 14
Economy teletext and TV microcontrollers
PWE
BIT
7
7
6
5
4
3
2
1
0
6-
Pulse Width Modulator Registers (PWM0 to PWM7)
BIT
PWM DAC
SYMBOL
PWE
PV5
PV4
PV3
PV2
PV1
PV0
6
S
If PWE is set to a logic 1, the corresponding PWM is active and controls its assigned
port pin. If PWE is set to a logic 0, the port pin is controlled by the corresponding bit in
the port SFR.
Not used.
The output of the PWM is a pulse of period 21.33 s with a pulse HIGH time determined
by the binary value of these 6-bits multiplied by 0.33 s. PV5 is the most significant bit.
PV5
5
PV4
4
12
PV3
3
DESCRIPTION
PV2
2
SAA5x9x family
Preliminary specification
PV1
1
PV0
0