VSC7440 datasheet(350/444 Pages) MICROSEMI

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VCore-III System and CPU Interfaces

VMDS-10492 VSC7440 Datasheet Revision 4.2

333

Figure 113 •

Injection Status Word Encoding

Injection logic updates the PD field of the status word. The status word can be read at any time during

injection without affecting current data block transfers. However, a CPU is able to calculate how much

data that is required to inject a complete block of data (at least BLOCKO + BLOCKL bytes), so reading

the status word is for software development and debug only. Writing status word before finishing a

previous data block will cause that frame to be aborted. Frames are also aborted if they do not start with

SOF or end with EOF indications.

As long as the status word is not written, multiple writes to the injection region are treated as data

belonging to the same block. This means multiple bursts of data words can be written between each

injection status word update.

Software can abort frames by writing to injection status with ABORT field set. All other status word fields

are ignored. When a frame is aborted, the already injected data is removed from the queuing system.

4.8

VCore-III System Peripherals

This section describes the subblocks of the VCore-III system. Although the subblocks are primarily

intended to be used by the VCore-III CPU, an external CPU can also access and control them through

the shared bus.

4.8.1

SI Boot Controller

The SPI boot master allows booting from a Flash that is connected to the serial interface. For information

about how to write to the serial interface, see SI Master Controller, page 335. For information about using

an external CPU to access device registers using the serial interface, see Serial Interface in Slave Mode,

page 312.

The following table lists the registers associated with the SI boot controller.

Table 245 •

SI Boot Controller Configuration Registers

Description

ICPU_CFG::SPI_MST_CFG

Serial interface speed and address width

ICPU_CFG::SW_MODE

Legacy manual control of the serial interface pins

ICPU_CFG::GENERAL_CTRL

SI interface ownership

[31:20]

[15:0]

BLOCKL: The amount of frame data (bytes) that

will be written for this block. The CPU is allowed to

write more data than this, additional data will be

ignored.

SOF: Start of frame, set to indicate that this block

contains start of a frame.

EOF: End of frame, set to indicate that this block

contains end of a frame.

ABORT: Set to abort active frame transfer. The

current frame will be aborted and removed from

Queuing System.

PD: Injection done, is set by the injection logic

when enough data has been received for this block

of data (BLOCKO+BLOCKL). If set when writing

status word, then this is treated as if ABORT had

been set.

BLOCKO: The amount of dummy bytes (non-frame

data) to expect before the frame data. The dummy

data will be ignored.

BLOCKL

BLOCKO

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