Version 2.3

CobraNet Hardware User’s Manual

Host Management Interface (HMI)

7.4 Protocol and Messages

The message conduit is used to issue commands to the CS1810xx/CS4961xx and

retrieve HMI status. The data conduit is used to transfer data dependent on the HMI state

as determined by commands issued by the host via the message conduit.

7.4.1 Messages

Messages are used to efficiently invoke action in the CS1810xx/CS4961xx. To send a

message, the host optionally writes to the A, B, and C registers. Writing to the D register

transmits the message to the CS1810xx/CS4961xx. A listing of all HMI messages is

shown in Tab l e 4. Refer also to "HMI Definitions" on page 33 and "HMI Access Code" on

page 34.

Table 4. HMI messages

Message

DRQ Handshake

Mode

A B C D

Translate Address n/c Address (MS) Address Address (LS) 0xB3

Acknowledge Interrupt n/c n/c n/c n/c 0xB4

Identify read n/c n/c 7 0xB5

Goto Packet Transmit

Buffer

write n/c n/c 6 0xB5

Goto Translation write n/c n/c 5 0xB5

Acknowledge Packet

Receipt

n/c n/c n/c 4 0xB5

Transmit Packet n/c n/c n/c 3 0xB5

Goto Counters read n/c n/c 2 0xB5

Goto Packet Receive

Buffer

read n/c n/c 1 0xB5

Goto Translation read n/c n/c 0 0xB5

CobraNet Hardware User’s Manual

Host Management Interface (HMI)

Version 2.3

7.4.1.1. Translate Address

Translate Address does not actually update the address pointers but initiates the

processing required to eventually move them. The host can accomplish other tasks,

including HMI Reads and Writes while the address translation is being processed. A

logical description of Translate Address is given below. A contextual use of the Translate

Address operation is shown in the reference implementations. Refer also to "HMI

Definitions" on page 33 and "HMI Access Code" on page 34.

void TranslateAddress(

long address )

{

int msgack = MSG_D;

MSG_A = ( address & 0xff0000 ) >> 16;

MSG_B = ( address & 0xff00 ) >> 8;

MSG_C = address & 0xff;

MSG_D = CVR_TRANSLATE_ADDRESS;

while( !( ( msgack ^ MSG_D ) & ( 1 << MSG_TOGGLE_BO ) ) );

}

7.4.1.2. Interrupt Acknowledge

Causes HACK to be de-asserted.

void InterruptAck( void )

{

int msgack = MSG_D;

MSG_D = CVR_INTERRUPT_ACK;

while( !( ( msgack ^ MSG_D ) & ( 1 << MSG_TOGGLE_BO ) ) );

}

7.4.1.3. Goto Packet

Moves HMI pointers to bridgeRxPktBuffer (write = 0) or bridgeTxPktBuffer (write = 1).

void GotoPacket(

bool write )

{

int msgack = MSG_D;

MSG_C = write ? MOP_GOTO_PACKET_TRANSMIT : MOP_GOTO_PACKET_RECEIVE;

MSG_D = CVR_MULTIPLEX_OP;

while( !( ( msgack ^ MSG_D ) & ( 1 << MSG_TOGGLE_BO ) ) );

}

7.4.1.4. Goto Translation

Moves HMI data pointers to the results of the most recently completed translate address

operation. The write parameter dictates the operation of the HREQ

signal and only needs

to be supplied for applications using hardware data handshaking via this signal.

void GotoTranslation(

bool write = 0 )

{

int msgack = MSG_D;

MSG_C = write ? MOP_GOTO_TRANSLATION_WRITE : MOP_GOTO_TRANSLATION_READ;

MSG_D = CVR_MULTIPLEX_OP;

while( !( ( msgack ^ MSG_D ) & ( 1 << MSG_TOGGLE_BO ) ) );

}

Version 2.3

CobraNet Hardware User’s Manual

Host Management Interface (HMI)

7.4.1.5. Packet Received

Sets bridgeRxPkt = bridgeRxReady thus acknowledging receipt of the packet in

bridgeRxPktBuffer.

void PacketReceive( void )

{

int msgack = MSG_D;

MSG_C = MOP_PACKET_RECEIVE;

MSG_D = CVR_MULTIPLEX_OP;

while( !( ( msgack ^ MSG_D ) & ( 1 << MSG_TOGGLE_BO ) ) );

}

7.4.1.6. Packet Transmit

Sets bridgeTxPkt = bridgeTxPktDone+1 thus initiating transmission of the contents of

bridgeTxPktBuffer. Presumably bridgeTxPktBuffer has been previously written with valid

packet data.

void PacketTransmit( void )

{

int msgack = MSG_D;

MSG_C = MOP_PACKET_TRANSMIT;

MSG_D = CVR_MULTIPLEX_OP;

while( !( ( msgack ^ MSG_D ) & ( 1 << MSG_TOGGLE_BO ) ) );

}

7.4.1.7. Goto Counters

Moves HMI data pointers to interrupt status variables (beginning at hackStatus).

void GotoCounters( void )

{

int msgack = MSG_D;

MSG_C = MOP_GOTO_COUNTERS;

MSG_D = CVR_MULTIPLEX_OP;

while( !( ( msgack ^ MSG_D ) & ( 1 << MSG_TOGGLE_BO ) ) );

}

Part #	CS496122-CQZ
Description	16X16 IC W/DSP C-NET INTERFACE PROC
Category	IC
Availability	Out of Stock
Qty	0

CS496122-CQZ

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