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CHAPTER 4 ATM CELL PROCESSOR
Preliminary User’s Manual S14767EJ1V0UM00
277
4.3 Interruption
When it sets a bit in A_GSR (General Status Register) which is NOT masked by the corresponding bit in A_IMR,
an interruption is sent out to V
R
4120A RISC Processor. The status of interruption is obtained by reading in A_GSR.
When V
R
4120A RISC Processor reads A_GSR, the bits which are set and are NOT masked by A_IMR will be reset.
The interruption can be masked by resetting bits of corresponding incidents in A_IMR (Interrupt Mask Register).
Interruptions from PHY devices are forwarded to V
R
4120A RISC Processor by PI bit of A_GSR automatically. RISC
core receives them as well.
4.4 Registers for ATM Cell Processing
Registers in this ATM Cell Processor block can be classified into 3 groups: SAR registers, DMA registers and FIFO
Control registers. These registers are mapped to both V
R
4120A RISC Processor memory space and RISC Core
memory space.
In the
μ
PD98405, There are two way to access to the registers from host: Direct-Access and Indirect-Access. But,
in this block, All registers are mapped to Direct-Access area. Indirect-Access is used only for peripherals, RISC Core
internal RAM and Work-RAM
4.4.1 Register map
Registers are used for SAR functions. V
R
4120A RISC Processor writes to these registers to control SAR functions
and read from these registers to know the status, while F/W on RISC Core read from these registers to know what
V
R
4120A RISC Processor wants and write to these registers to indicate the status of ATM Cell Processor.
In the next page, indicate the Register Map for this ATM cell Processor.
4.4.1.1 Direct addressing register
(1/2)
Address
Note
Register
Description
Read/Write
F000H
A_GMR
General Mode Register
R/W
F004H
A_GSR
General Status Register
R
F008H
A_IMR
Interrupt Mask Register
R/W
F00CH
A_RQU
Receive Queue Underrunning
R
F010H
A_RQA
Receive Queue Alert
R
F014H
N/A
Reserved for future use
X
F018H
A_VER
Version Number
R
F01CH
N/A
Reserved for future use
-
F020H
A_CMR
Command Register
R/W
F024H
N/A
Reserved for future use
-
F028H
A_CER
Command Extension Register
R/W
F02CH-F04CH
N/A
Reserved for future use
-
F050H
A_MSA0
Mailbox0 Start Address
R/W
F054H
A_MSA1
Mailbox1 Start Address
R/W
F058H
A_MSA2
Mailbox2 Start Address
R/W
F05CH
A_MSA3
Mailbox3 Start Address
R/W
F060H
A_MBA0
Mailbox0 Bottom Address
R/W
F064H
A_MBA1
Mailbox1 Bottom Address
R/W
Note
V
R
4120A RISC Processor memory space, add 1001_0000H as Base Address.