TOSHIBA
TMPR3904F Rev. 2.0
119
26
DMAC0 and DMAC1 are daisy-chain connected. When DMAC0 and DMAC1 are both using
the snoop function or are both not using it, the priority is determined by the daisy-chain
connection; and DMAC0 has a higher priority than DMAC1.
When DMAC0 and DMAC1 simultaneously request of the TX39 Processor Core for the bus
ownership, DMAC0 is granted the bus ownership to start a transfer operation. DMAC1 cannot
start a transfer until DMAC0 releases the bus ownership.
Even if DMAC0 requests the bus ownership when DMAC1 has the bus ownership, the bus
ownership shall not be transferred to DMAC0 immediately. DMAC0 is made to wait until
DMAC1 releases the bus ownership.
(2) Priority by bus ownership request modes
When the bus ownership requests are different; namely, when one DMAC is using the SREQ
and the other DMAC the GREQ, the DMAC using SREQ has a higher priority.
When the DMAC using SREQ and the DMAC using GREQ simultaneously request the bus
ownership, the DMAC using SREQ obtains the bus ownership.
If the DMAC using SREQ requests the bus ownership while the DMAC using GREQ is
transferring data, the bus arbiter in the TX39 processor core requests the bus ownership at a
break of the data transfer. If the DMAC using GREQ answers to the request from the bus
arbiter, the bus ownership is transferred to the DMAC using SREQ. However, if the RelEn is
cleared to 0 in the CCRn of the DMAC using GREQ (if the bus ownership release request is not
answered), the DMAC using GREQ does not release the bus ownership and continues the data
transfer.
Содержание TMPR3904F
Страница 1: ...Users Manual 32bit RISC Microprocessor TX39 family TMPR3904F Rev 2 0 Jan 12 1998 ...
Страница 2: ......
Страница 9: ...Users Manual 01 1 INTRODUCTION 1 1 Overview ...
Страница 10: ...Users Manual 02 1 2 Notation used in this manual Mathematical notation Data notation Signal notation ...
Страница 11: ...Users Manual 03 1 3 Kind of accessing by the TX3904 ...
Страница 12: ...Users Manual 04 1 4 Precautions in the TMPR3904F specification Don t set Don t use ...
Страница 13: ...Users Manual 05 Do not use ...
Страница 14: ...Users Manual 06 ...
Страница 15: ...Users Manual 7 2 FEATURES n n n n n n n n n n n n n ...
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Страница 19: ...Users Manual 11 4 PINS 4 1 Positions of Pins ...
Страница 20: ...Users Manual 12 ...
Страница 21: ...Users Manual 13 4 2 Functions of Pins ...
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Страница 26: ...Users Manual 18 5 2 Register Map ...
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Страница 30: ...Users Manual 22 5 3 2 PIO2 and PIO1 ...
Страница 32: ...Users Manual 24 5 3 4 Connection of external bus master 5 3 5 INT 7 0 active status clear ...
Страница 33: ...Users Manual 25 5 3 6 INT 7 0 active status set up ...
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