ZR36057 Просмотр технического описания (PDF) - Zoran Corporation

Номер в каталоге

Компоненты Описание

Список матч

ZR36057

ENHANCED PCI BUS MULTIMEDIA CONTROLLER

Zoran Corporation 

Enhanced PCI Bus Multimedia Controller

10.0 RESET

There are three means of resetting the ZR36057. One is a

hardware reset, which is applied through the PCIRST input, the

second is a software reset, which is applied through the SoftRe-

set register bit. The third is the JPEG Process Reset asserted by

the P_reset register bit.

10.1 Hardware Reset

The hardware reset signal PCIRST resets the internal state

machines in the ZR36057 and loads all registers with their

default states. The reset state of the PCI interface pins is as

defined by the PCI specifications (2.1). The reset state of the

other output/bidirectional signals is as follows.

The GPIO[7:0] lines are all inputs after reset. If required for

system purposes, they can be pulled high or low through 1 K

external resistors to have fixed values on reset.

As long as PCIRST is asserted, the following signals are tri-

stated: GDAT[7:0], GADR[2:0], GCS[3:0], GWR, GRD, SDA,

SCL. Once the PCIRST input is deasserted, these signals go to

their software reset condition (as does the entire device).

A hardware reset asserts (clears) the SoftReset bit in the system

register. After the hardware reset is over, the ZR36057 will be in

software reset condition until the SoftReset bit is deasserted.

10.2 Software Reset

There are two ways in which the ZR36057 can go into the

software reset condition: one is right after hardware reset (i.e.,

upon the low to high transition of PCIRST), the other is by

clearing the SoftReset bit.

While in software reset, all registers and state machines in the

device are reset to their default values/states, except the Soft-

Reset bit itself, and the PCI Interface (including the PCI

configuration space registers).

The device continues to respond according to the PCI Specifica-

tion and can be the target of a PCI transfer targeted at the ASRs

(Application Specific Registers) or PCI Configuration Space.

While in software reset the device will not initiate any PCI trans-

fers, because all DMA channels are disabled.

After the SoftReset bit is deasserted, all registers retain their

default values, all DMA channels remain disabled and all ASRs

are programmable according to their “normal” modification

conditions.

Hence, the initialization of the device (loading all registers with

the values required for the specific application) must start with

setting SoftReset to ‘1’, otherwise new ASR values will not be

latched in.

10.3 JPEG P_reset

The P_reset bit resets all of the JPEG related state machines

and controls in the ZR36057.

The P_reset bit enables re-configuration of all JPEG parameters

with no effect on the other functions of the device.

Before starting a new JPEG process, and while loading new

JPEG parameters, the P_reset bit must be asserted.

23

Share Link: