Maxim-integrated High-Speed Microcontroller Users Guide: Network Mi Manuale Utente Scaricare il pdf (Pagina 185)

High-Speed Microcontroller User’s

Guide: Network Microcontroller

Supplement

185

Figure 22-12. Transmit Flow Diagram

CPU

Load transmit data buffer memory (MOVXs)

Write BCUD SFR

(Data buffer size/location)

1) msbyte of 11-bit transmit buffer byte count [00–06h]

2) lsbyte of 11-bit transmit buffer byte count [00–FFh]

3) Starting page of transmit buffer [00–1Fh]

Write BCUC SFR

With transmit request command:

BCUC.3-0 Command

0100 Transmit — Normal

0101 Transmit—No zero-padding of data

0110 Transmit—No FCS appended

ETHERNET CONTROLLER

BCU

CPU RUNS OTHER

APPLICATION CODE

BCU services transmit request

1) Transmit attempt by MAC completes or aborts

2) Transmit status word written to the data buffer

3) Transmit interrupt flag (TIF) set to 1

Ethernet activity interrupt request (if enabled)

1) Read BCUC to find TIF = 1

2) Read transmit status word for packet handling

Maxim Integrated

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Maxim-integrated High-Speed Microcontroller Users Guide: Network Mi Manuale Utente Pagina 185