ZR36060PQC datasheet(23/46 Pages) ETC

23 / 46 page

Integrated JPEG CODEC

6.0 OPERATION

6.1 ZR36060 Functional States

For the purposes of this description, the ZR36060 can be viewed

as having 7 states:

• RESET - In this state the RESET input is held active.

• SLEEP - Power-down. The SLEEP input is held active in this

state.

• IDLE - END is asserted and the ZR36060 is waiting for

START.

• WAIT-ACTIVE - After the ZR36060 sensed START assert-

ed, it waits for the beginning of the active area of the next

field to be processed (this depends on the state of FRAME

when START was sampled active). END is deasserted.

• CMP - Compression of the active area. The video bus is in-

put, and the code data bus is output. END is deasserted.

• EXP - Decompression (expansion) of the active area. The

video bus is output, and the code data bus is input. END is

deasserted.

• WAIT-ISR - After the ZR36060 finished the compression or

decompression and asserted END while JIRQ is active (due

to a non-masked interrupt), the ZR36060 waits in this state

for the host to read the Interrupt Status Register.

6.2 State Transitions

Figure 28 depicts the states and their transitions.

6.3 The SLEEP State

In this state, all the pins remain in the logic states they were in

immediately before the transition to SLEEP. No host, video or

code interface operation is allowed in the SLEEP state.

When the ZR36060 leaves the SLEEP state it returns to IDLE,

ready for the next compression or decompression operation.

This state is also used internally to lock the internal PLL to the

frequency of VCLKx2, so it is mandatory to go through the

SLEEP state at least once after power-up and before operating

the device (see section 7.0 “Power Management and Power-

up”).

6.4 Loading Parameters and Tables

Prior to a compression or decompression process the host must

load the appropriate parameters and tables into the ZR36060.

The parameters affect the compression/decompression mode,

the video interface, and the operation of the code port.

All parameters and tables may be loaded only when the

ZR36060 is in the IDLE state.

First, the host controller writes (via the host interface) the desired

parameters and/or tables in their correct location in the 1Kbyte

internal memory (see chapter 8.0 “Register and Memory

Description” for details).

Then, the host sets the ZR36060’s (write-only) Load bit. This

commands the ZR36060 to initialize or ‘Load’ all internal

hardware blocks with the parameters in its internal memory, and

also to decode and expand the abbreviated format Huffman and

Quantization tables. While the ZR36060 is performing this Load

operation, the (read-only) Busy bit is set to ‘1’. The host must poll

for the completion of the loading, i.e.- wait for the Busy bit to be

reset to ‘0’, before starting the compression or decompression

process.

The START signal is ignored during the execution of the Load,

i.e.- the ZR36060 remains in the IDLE state (with END asserted).

Only after Load is completed (Busy is reset) and the new param-

eter values become effective, the ZR36060 is ready to sample

START again to move to the WAIT-ACTIVE state to start the

compression/decompression process (see Figure 29).

Parameters and status registers can be read in any ZR36060

state (besides RESET and SLEEP).

WAIT

ACTIVE

RESET

Power-Up

RESET

! SLEEP &

! RESET

SLEEP

SLEEP &! RESET

SLEEP

Figure 28. ZR36060 Functional States

! SLEEP

IDLE

! START

START

! (active area)

EXP

CMP

active area[1]

& compression

active area[1] &

decompression

END & ! JIRQ

JIRQ

END & JIRQ

WAIT ISR

! JIRQ

Active area of the correct field, depending on the state of

FRAME when START was sampled active.

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