TOSHIBA
TMPR3904F Rev. 2.0
124
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13
PosE
Rising edge
Positive Edge
Designates the valid level of the transfer request signal
DREQn. This is valid only when the transfer request is
an external transfer request (the ExR bit is 1). When it is
an internal transfer request (the ExR bit is 0), the value of
the PosE shall be ignored. There are the edge detection
and the level detection as the methods to acknowledge
the DREQn signal; and they are set up in the Lev bit.
The active level of the transfer acknowledge signal
DACKn is the same as the active level of the DREQn
signal.
1: The rising or the high level of the DREQn signal
is valid. The active level of the DACKn signal
is high.
0: The falling or the low level of the DREQn signal
is valid. The active level of the DACKn signal
is low.
12
Lev
Level mode
Level Mode
Designates the request method of the external transfer
request. This is valid only when an external transfer
request is set up (the ExR bit is 1) as the transfer request.
When an internal transfer request (the ExR bit is 0) is set
up, the value of the Lev bit shall be ignored. The valid
level of the DREQn signal is set up in the PosE bit.
1: Level mode. Acknowledges the levels (the low level
when the PosE bit is 0 and the high level when the PosE
bit is 1) of the DREQn signal as data transfer requests.
0: Edge mode. Acknowledges changes (the falling edge
when the PosE bit is 0 and the rising edge when the PosE
bit is 1) in the DREQn signal as data transfer requests.
11
SReq
Snoop request
SReq (Snoop Request)
Designates whether or not to use the snoop function as
the bus ownership request mode. When using it, the
snoop function of the TX39 Processor Core becomes
valid; and the TX39 Processor Core watches the address
of the DMA transfer. When not using it, the snoop
function of the TX39 Processor Core does not function.
1: Snoop function is used (SREQ).
0: Snoop function is not used (GREQ).
The GREQ is not able to be used in the TX3904F.
Fig. 10-6 Channel Control Registers (CCRn) (3/4)
Содержание TMPR3904F
Страница 1: ...Users Manual 32bit RISC Microprocessor TX39 family TMPR3904F Rev 2 0 Jan 12 1998 ...
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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 ...
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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 ...
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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 ...
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