EP9312-CB Cirrus Logic Inc, EP9312-CB Datasheet - Page 421

• Manufacturer Part Number: EP9312-CB
• Description: System-on-Chip Processor
• Manufacturer: Cirrus Logic Inc
• Series: EP9r

Specifications of EP9312-CB

• Peak Reflow Compatible (260 C): No
• A/d Converter: 12 Bits
• Leaded Process Compatible: No
• No. Of I/o Pins: 65
• Package / Case: 352-BGA
• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 200MHz
• Connectivity: EBI/EMI, EIDE, Ethernet, I²C, IrDA, Keypad/Touchscreen, SPI, UART/USART, USB
• Peripherals: AC'97, DMA, I&sup2:S, LCD, LED, MaverickKey, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Type: ROMless
• Ram Size: 32K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 3.6 V
• Data Converters: A/D 8x12b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Processor Series: EP93xx
• Core: ARM920T
• Data Bus Width: 32 bit
• 3rd Party Development Tools: MDK-ARM, RL-ARM, ULINK2
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Lead Free Status / Rohs Status: No
• Other names: 598-1257

DS785UM1
Current State:
NextBuffer:
Copyright 2007 Cirrus Logic
Indicates the state that the Channel FSM is currently in:
00 - IDLE
01 - STALL
10 - ON
11 - NEXT
Informs the NFB service routine, after a NFB interrupt,
which pair of BASEx/MAXCOUNTx registers is free for
update.
0 - Update MAXCNT0/BASE0
1 - Update MAXCNT1/BASE1
The NextBuffer bit gets set to “1” when a write occurs to
BASE0 and it gets set to “0” when a write occurs to
BASE1. This bit alone cannot be used to determine which
of the two buffers is currently being transferred to. For
example, if BASE0 is written to, then NextBuffer gets set
to “1” and transfers will occur using buffer0. If, during this
transfer BASE1 gets written to, then NextBuffer gets set to
“0”, but the current transfer will continue using buffer0 until
it terminates. Then the DMA switches over to using
buffer1, at which time the NFB interrupt is generated and
software reads the NextBuffer status bit to determine what
buffer descriptor is now free for update. In this case it is
buffer0.
The NextBuffer status bit can be used in conjunction with
the CurrentState status bits to determine the active buffer.
If CurrentState = DMA_ON and NextBuffer = 1 then
Buffer0 is the active buffer.
If CurrentState = DMA_ON and NextBuffer = 0 then
Buffer1 is the active buffer.
If CurrentState = DMA_NEXT and NextBuffer = 0 then
Buffer0 is the active buffer.
If CurrentState = DMA_NEXT and NextBuffer =1 then
Buffer1 is the active buffer.
EP93xx User’s Guide
DMA Controller
10-27
10