Section 6 Bus Controller
Rev. 3.00 Jan 25, 2006 page 137 of 872
REJ09B0286-0300
6.7
Memory Card Interface
A CP expansion area can be set to the CF expansion area (memory card mode) by setting both the
CPCSE bit in BCR2 to 1 and the CFE bit in BCR to 1. In memory card mode, the bus width is
fixed to 16 bits. In this mode, signal pins other than
CPCS1
and
CPCS2
are common to the basic
bus interface, but their signal waveforms differ. The number of access states and waveforms of the
strobe signals (
CPOE
and
CPWE
) can be controlled by the WMS21, WMS20, WC22, WC21, and
WC20 bits in WSCR2 and the OWEAC and OWENC bits in BCR2.
6.7.1
Data Size and Data Alignment
The data sizes for the CPU and other internal bus masters are byte, word, and longword. The BSC
has a data alignment function, and controls whether the upper data bus (D15 to D8) or lower data
bus (D7 to D0) is used when the CF expansion area is accessed in memory card mode according to
the accessed data size.
Figure 6.16 illustrates the data alignment control. In CF expansion area access, the upper data bus
(D15 to D8) and lower data bus (D7 to D0) are used. The amount of data that can be accessed at
one time is one byte or one word: a longword access is performed as two word accesses.
D15
D8 D7
D0
Upper data bus
: Even data
: Odd data
Lower data bus
Byte size
Word size
1st bus cycle
2nd bus cycle
Longword
size
• Even address
Byte size
• Odd address
Figure 6.16 Access Sizes and Data Alignment Control
Содержание H8S/2158
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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...
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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...