TX4939XBG-400 Toshiba, TX4939XBG-400 Datasheet - Page 444

• Manufacturer Part Number: TX4939XBG-400
• Manufacturer: Toshiba

Specifications of TX4939XBG-400

• Cpu Core: TX49/H4 90nm
• Clock Mhz/max Mips: 400/520
• Inst./data Cache: 32KB (4 Way)/32KB (4 Way)
• Tlb: x
• 1cycle Mac: x
• Volts (v): 1.25/2.5/3.3
• Peripherals: DDR, NAND, ATA, ETHERNET, SECURITY, FPU, MMU, SPI, I2S, I2C, PCI, VIDEO, UART, TIMER, RTC
• Companion Chip: TC86C001FG
• Package: PGBA456

PCIC
Rev. 3.1 November 1, 2005
Bit
7
6
5
4
3:2
1
0
Mnemonic
CHNEN
XFRACT
BSWAP
XFRSIZE
XFRDIRC
CHRST
Field Name
Chain Enable
Transfer Active
Rsvd
Byte Swap Within
DWORD
Transfer Size
Transfer Direction Transfer Direction (Default: 0x0)
Channel Reset
Table 16-74 PDMAC Control Register
Description
Chain Enable (Default: 0x0) (Read Only)
When the current data transfer is complete, this field reads the next data
command Descriptor from the address indicated by the PDMAC Chain
Address Register then indicates whether to continue the transfer or not.
This bit is only set to “1” when either a CPU Write process or a Descriptor
Read process sets a value other than “0” in the PDMAC Chain Address
Register.
This bit is cleared to “0” if either the Channel Reset bit is set, or “0” is set in the
PDMAC Chain Address Register by a CPU Write or a Descriptor Read
process.
The above 0 value judgement is not performed when the TX49/H4 core
stores the upper 32 bits in the PDMAC Chain Address Register.
1: Reads the next data command Descriptor.
0: Does not read the next data command Descriptor.
Transfer Active (Default: 0x0)
Specifies whether to perform DMA transfer or not.
Setting this bit after setting the appropriate value in the register group initiates
DMA data transfer.
This bit is not set if the PDMAC Count Register value is “0” and the Chain
Enable bit is cleared when “1” is written to this bit.
Even when a value other than “0” is written to the Chain Address Register, “1”
is set to this bit and DMA transfer automatically starts.
The above 0 value judgement is not performed when the TX49/H4 core
stores the upper 32 bits in the PDMAC Chain Address Register.
Data transfer will be stopped after a short delay if this bit is cleared while the
data transfer is in progress.
This bit is automatically cleared to “0” either when data transfer ends normally
or is stopped by an error.
Never clear XFRACT by software, because it stops guaranteeing a normal
operation,.
1: Perform data transfer.
0: Do not perform data transfer.
Swap Bytes in DWORD (Default: 0x0)
Specifies whether to perform 32-bit data byte swapping.
Please leave this bit at “0” for normal usage.
Setting this bit when in the Big Endian mode executes data transfer so the
byte order of the 32-bit data on the PCI Bus (which is Little Endian) does not
change.
1: Swap the byte order of each 32-bit DWORD data, then transfer.
0: Transfer without swapping the byte order of each 32-bit DWORD data.
Transfer Size (Default: 0x0)
Specifies the data transfer size in one G-Bus transaction on the G-Bus.
00: 1 DWORD (32-bit)
01: 1 QWORD (64-bit)
10: 4 QWORD (Burst transfer)
11: Rsvd
Specifies the DMA data transfer direction.
1: Transfers data from the G-Bus to the PCI Bus.
0: Transfers data from the PCI Bus to the G-Bus.
Channel Reset (Default: 0x1)
Resets the DMA channel.
This bit must be cleared by the software in advance so the channel can start
the data transfer. This reset function is not supported when PDMAC is in
operation.
Ensure that the Transfer Active (XFARCT) bit in the PDMSTATUS register is
cleared prior to resetting the DMA channel. For chained DMA, also ensure
either the Abnormal Chain Complete (ACCMP) or Normal Chain Complete
(NCCMP) bit in the PDMSTATUS register is set.
1: All logic and State Machines are reset.
0: The channel becomes valid.
16-80
Toshiba RISC Processor
R/W
R
R/W
⎯
R/W
R/W
R/W
R/W
TX4939
16
16