isp1161bm NXP Semiconductors, isp1161bm Datasheet - Page 14

• Manufacturer Part Number: isp1161bm
• Description: Isp1161 Full-speed Universal Serial Bus Single-chip Host And Device Controller
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 09567
Product data
8.3.2 Register access phases
ISP1161’s register structure is a command-data register pair structure. A complete
register access cycle comprises a command phase followed by a data phase. The
command (also known as the index of a register) points the ISP1161 to the next
register to be accessed. A command is 8 bits long. On a microprocessor’s 16-bit data
bus, a command occupies the lower byte, with the upper byte filled with zeros.
Figure 12
microprocessor writes a command code to the command port, and then reads from or
writes the data word to the data port. Take the example of a microprocessor
attempting to read a chip’s ID, which is saved in the HC’s HcChipID register (27H,
read only) where its command code is 27H, read only. The 16-bit register access
cycle is therefore:
1. Microprocessor writes the command code of 27H (0027H in 16-bit width) to
2. Microprocessor reads the data word of the chip’s ID from ISP1161’s HC data
Fig 10. A microprocessor accessing a HC or a DC via an automux switch.
Fig 11. Access to internal control registers.
ISP1161’s HC command port
port.
When A1 = 0, microprocessor accesses the HC.
When A1 = 1, microprocessor accesses the DC.
When A0 = 0, microprocessor accesses the data port.
When A0 = 1, microprocessor accesses the command port.
shows a complete 16-bit register access cycle for ISP1161. The
Host or Device
Rev. 02 — 13 December 2002
bus I/F
A0
CMD/DATA
Full-speed USB single-chip host and device controller
SWITCH
P bus I/F
1
0
A1
data port
command port
AUTOMUX
DC/HC
0
1
Control registers
Device bus I/F
Host bus I/F
. .
.
© Koninklijke Philips Electronics N.V. 2002. All rights reserved.
MGT935
Command register
Commands
MGT936
ISP1161
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