Datasheet

ENC424J600/624J600
DS39935C-page 42  2010 Microchip Technology Inc.
TABLE 4-2: SINGLE BYTE INSTRUCTIONS
4.4 Two-Byte Instructions
There is only one instruction in the ENCX24J600 com-
mand set which uses two SPI bytes. The Read Bank
Select opcode, RBSEL, reads the internal SFR bank
select state and returns the value to the host controller.
Figure 4-2 shows the timing relationships for perform-
ing the two-byte operation. The first byte of the opcode
(‘11001000’) must be presented on the SI pin, MSb
first, followed by “don’t care” values for the second byte
(9
th
through 16
th
SCK rising edges). The bank select
value (00h through 03h) is returned on the SO pin, MSb
first, while the second byte is being presented on the SI
pin.
Because this instruction is a fixed length with no
optional parameters, it is possible to execute any
instruction following the execution of RBSEL without
deasserting the chip select line in between.
Since this opcode does not modify the ENCX24J600
internal state, it can be aborted at any time by returning
the CS
pin to the inactive state.
FIGURE 4-2: TWO-BYTE INSTRUCTION TIMING (RBSEL OPCODE)
Mnemonic Opcode Instruction
B0SEL 1100 0000 Selects SFR Bank 0
B1SEL 1100 0010 Selects SFR Bank 1
B2SEL 1100 0100 Selects SFR Bank 2
B3SEL 1100 0110 Selects SFR Bank 3
SETETHRST 1100 1010 Issues System Reset by setting ETHRST (ECON2<4>)
FCDISABLE 1110 0000 Disables flow control (sets ECON1<7:6> = 00)
FCSINGLE 1110 0010 Transmits a single pause frame (sets ECON1<7:6> = 01)
FCMULTIPLE 1110 0100 Enables flow control with periodic pause frames (sets ECON1<7:6> = 10)
FCCLEAR 1110 0110 Terminates flow control with a final pause frame (sets ECON1<7:6> = 11)
SETPKTDEC 1100 1100 Decrements PKTCNT by setting PKTDEC (ECON1<8>)
DMASTOP 1101 0010 Stops current DMA operation by clearing DMAST (ECON1<5>)
DMACKSUM 1101 1000 Starts DMA and checksum operation (sets ECON1<5:2> = 1000)
DMACKSUMS 1101 1010 Starts DMA checksum operation with seed (sets ECON1<5:2> = 1010)
DMACOPY 1101 1100 Starts DMA copy and checksum operation (sets ECON1<5:2> = 1100)
DMACOPYS 1101 1110 Starts DMA copy and checksum operation with seed (sets ECON1<5:2> = 1110)
SETTXRTS 1101 0100 Sets TXRTS (ECON1<1>), sends an Ethernet packet
ENABLERX 1110 1000 Enables packet reception by setting RXEN (ECON1<0>)
DISABLERX 1110 1010 Disables packet reception by clearing RXEN (ECON1<0>)
SETEIE 1110 1100 Enable Ethernet Interrupts by setting INT (ESTAT<15>)
CLREIE 1110 1110 Disable Ethernet Interrupts by clearing INT (ESTAT<15>)
CS
SCK
SI
SO x x x x x x x xHi-Z Hi-Zx0
0 1 0 0
d d
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
RBSEL Opcode
SFR Bank Select
1 01
0 0 0 00