Motorola MC68328 Información técnica descargar pdf (Pagina 36)

3-18 FLEX Alphanumeric Chip MC68175 Interface

Software Development

Porting FLEX One-Way Stack to the MC68328 MPU

FStkNotifyNewMsg()

The FStkNotifyNewMsg() function is called each time FLEX One-Way Stack software

receives a new and completed FLEX message from the FLEX Alphanumeric Chip IC.

The message ID is passed to this function. Product engineers should implement this

function according to the product specifications. For example, FStkNotifyNewMsg() can

alert the user (with sounds or vibration) and/or retrieve the message from FLEX

One-Way Stack and display it on the screen or LCD. In Example 3-7, the new message

ID is simply stored in an array, and function GetPage() is called to display the message on

the LCD.

Send_4_bytes()

The Send_4_Bytes() function sends 4-byte packets to the FLEX Alphanumeric Chip using

the SPI. FLEX One-Way Stack uses this function to initiate the configuration process by

sending the FLEX Alphanumeric Chip a series of packets from the initialization buffer

(described earlier). This is the communication initiated by the host, so that the host

processor must first drive the FLEX Alphanumeric Chip chip-select signal low to start

the communication process. The actual SPI communication happens through the

interrupt service routine.

Example 3-7 Function FStkNotifyNewMsg() Sample

void FStkNotifyNewMsg(MSG msg)

{

UVAR8 i;

* If the new message overflows the array (storage of messages),

* pop the oldest message off the array for storage.

if (pageCount >= MSGTABLESZ)

MMMakeRoom();

/* Store message in the message table */

msgtable[pageCount] = msg->msgId;

GetPage(msg->msgId); /* Retrieve message for display */

pageCount++; /* Increase the number of pages */

}

Frees

cale Semiconductor,

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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Motorola MC68328 Información técnica Pagina 36