Section 8 RAM-FIFO Unit (RFU)
Rev. 3.00 Jan 25, 2006 page 184 of 872
REJ09B0286-0300
8.4
RAM-FIFO Location
The RAM-FIFO should be allocated at the addresses H'(FF)E080 to H'(FF)EFFF and H'FF0800 to
H'FF1FFF in on-chip RAM. Do not allocate the RAM-FIFO at the external address space.
8.5
RAM-FIFO Pointer
The RAM-FIFO specifies the start address by BAR, and the size by the BUD2 to BUD0 bits in
DTCRA. BAR and the BUD2 to BUD0 bits in DTCRA should be set so that the RAM-FIFO areas
of all pointer sets are stored in the on-chip RAM area, and the RAM-FIFO areas do not overlap
inter-pointer sets.
The RAM-FIFO can be accessed when the value of the sum of the contents of BAR and either the
contents of RAR, WAR, TMP, is output to the address bus.
8.6
RAM-FIFO Manipulation and RFU Bus Cycles
Table 8.4 summarizes the requests from the peripheral modules to the RFU and manipulations of
the RFU bus cycle and pointer.
The RFU returns an acknowledge signal for a request from the peripheral modules to clear the
request. All RFU bus cycles are executed in two states. In the RFU bus cycle, data transfer is
executed or the error status is notified in addition to clearing a request and the RFU pointer is
manipulated simultaneously. In data transfer in the RFU bus cycle, the RAM address is output to
the address bus, the ID of the peripheral module is specified, and data transfer from RAM to the
peripheral module or from peripheral module to RAM is executed in one bus cycle,
simultaneously. An RFU bus cycle other than the read/write cycle is two states.
There are four types of requests from the peripheral modules: Data transfer, pointer mark
(RAR/WAR
→
TMP), pointer reload (TMP
→
RAR/WAR), and pointer reset (0
→
RAR, WAR,
TMP).
When data transfer is executed, either RAR or WAR is added for the number of transfer bytes,
according to the settings of the transfer direction and the byte/word transfer. As one TMP is
provided in a pointer set, TMP is used as either the read temporary pointer or write temporary
pointer.
If the added contents exceed the FIFO size specified by bits BUD2 to BUD0 in DTCRA, the
pointer is set to a value from which the FIFO size is decremented (remainder of the FIFO size).
Содержание H8S/2158
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Страница 126: ...Section 4 Exception Handling Rev 3 00 Jan 25 2006 page 72 of 872 REJ09B0286 0300...
Страница 198: ...Section 6 Bus Controller Rev 3 00 Jan 25 2006 page 144 of 872 REJ09B0286 0300...
Страница 326: ...Section 10 8 Bit PWM Timer PWM Rev 3 00 Jan 25 2006 page 272 of 872 REJ09B0286 0300...
Страница 440: ...Section 15 Watchdog Timer WDT Rev 3 00 Jan 25 2006 page 386 of 872 REJ09B0286 0300...
Страница 606: ...Section 17 I 2 C Bus Interface IIC Rev 3 00 Jan 25 2006 page 552 of 872 REJ09B0286 0300...
Страница 742: ...Section 19 Multimedia Card Interface MCIF Rev 3 00 Jan 25 2006 page 688 of 872 REJ09B0286 0300...
Страница 744: ...Section 20 Encryption Operation Circuit DES and GF Rev 3 00 Jan 25 2006 page 690 of 872 REJ09B0286 0300...
Страница 750: ...Section 21 D A Converter Rev 3 00 Jan 25 2006 page 696 of 872 REJ09B0286 0300...
Страница 768: ...Section 22 A D Converter Rev 3 00 Jan 25 2006 page 714 of 872 REJ09B0286 0300...
Страница 770: ...Section 23 RAM Rev 3 00 Jan 25 2006 page 716 of 872 REJ09B0286 0300...
Страница 824: ...Section 26 Clock Pulse Generator Rev 3 00 Jan 25 2006 page 770 of 872 REJ09B0286 0300...
Страница 844: ...Section 27 Power Down Modes Rev 3 00 Jan 25 2006 page 790 of 872 REJ09B0286 0300...
Страница 878: ...Section 28 List of Registers Rev 3 00 Jan 25 2006 page 824 of 872 REJ09B0286 0300...
Страница 926: ...Index Rev 3 00 Jan 25 2006 page 872 of 872 REJ09B0286 0300...