SAA8117HL View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

SAA8117HL

Digital camera USB interface IC

Philips Electronics 

Philips Semiconductors

Digital camera USB interface IC

Product specification

SAA8117HL

8.4 Transfer buffer

The transfer buffer module (see Fig.1) ensures a smooth

transfer of the data to the FIFO of the USB. Moreover the

transfer buffer can insert in band synchronization words in

the video data stream.

This function can be switched on and off with

SN_In band_Control in register CONTROL17_0.

The synchronization words can only be used with

non-compressed data streams and are formatted like

0x00 0xFF 0x<framecounter>7<linecounter>9.

The subscript denotes the number of bits and the frame

counter is circular incrementing.

The non-compressed data is formatted like:

4 : 2 : 0: <optional sync word><Y0><Y1><Y2><Y3>

<C0><C2><Y4><Y5><Y6><Y7><C4><C6>....,

4 : 2 : 2: <optional sync word><Y0><Y1><Y2><Y3>

<U0><V0><U2><V2><Y4>....,

where C denotes U-data in the even lines (0, 2, 4, etc.)

and V-data in the odd lines (1, 3, 5, etc.).

8.5 SNERT interface

In a USB camera the SAA8110G will operate on a clock

frequency which depends on the actual frame rate. For the

slowest frame rates, this frequency can be so low that the

SNERT communication is no longer functional over the

specified entire frequency range of the microcontroller.

The microcontroller must adapt its SNERT bus frequency

to a frequency appropriate for the current mode in which

the SAA8110G is operating.

The SAA8117HL itself is also partly controlled via SNERT.

The CIF formatter, compression engine and the PPG

function are controlled via SNERT. This SNERT interface

works independently from the frame rate and can always

be operated in the full frequency range.

8.6 Sensor pulse generator

The SAA8117HL incorporates a Pulse Pattern Generator

(PPG) function. The PPG can be used for PAL medium

resolution Sharp sensors (LZ2423) or compatible CCD

sensors. The SAA8117HL can also handle VGA type CCD

sensors, so a set of pulses is provided to simplify the use

of such sensors. Depending on the type of sensor, it will be

necessary to reformat these pulses externally according to

the sensor specification.

It should be noted that in case of medium resolution Sharp

or compatible sensors an external inverter driver is

required to convert the 3 V pulses into a voltage suitable

for the used CCD sensor. For the medium resolution Sharp

CCD sensor driver, the name of the pins to which the PPG

pulses must be connected are indicated between brackets

in the SAA8117HL pinning list (pins C3, B1 and B2 are not

used).

For both type of sensors the PPG generates 8 different

frame rates (see Table 6). The active video size is

512 × 288 for PAL and 640 × 480 for VGA. The total H × V

size is 685 × 292 for PAL and 823 × 486 for VGA.

It should be noted that additional HD pulses are added

during the vertical blanking interval to reach a total of

312 lines in PAL mode and 525 lines in VGA mode as

required by the SAA8110G.

The following registers are associated with the PPG:

• CONTROL17_0

• CONTROL17_2

• PPG_SHUTTERSPEED_0

• PPG_SHUTTERSPEED_1

• PPG_CLPOB_START_LSB

• PPG_CLPOB_STOP_LSB

• PPG_CLPDM_START_LSB

• PPG_CLPDM_STOP_LSB

• CLPMSB.

8.7 Pulse diagrams

For medium resolution CCD sensors (PAL):

• High-speed pulses, see Figs 4 and 5

• Horizontal pulses, see Fig.6

• Vertical pulses, see Figs 7 to 11.

For VGA-sensors:

• High-speed pulses, see Figs 12 to 14

• Horizontal pulses, see Fig.15

• Vertical pulses, see Figs 16 to 21.

1999 Apr 02

11

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