ꢀꢁ ꢂꢃ ꢄ ꢅ ꢆ ꢇ ꢀ ꢁꢂ ꢃ ꢄꢅ ꢈ
ꢀꢁꢂ ꢃ ꢄ ꢅ ꢉ ꢇ ꢀ ꢁꢂ ꢃ ꢄꢅ ꢄ
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SLES081A − JUNE 2003 – REVISED MAY 2004
EXTERNAL ROM EXAMPLE
Here is an example of external ROM data, with an explanation of the example following the data.
0xBB, 0x08, 0x04, 0x27,
0x50, 0x72, 0x6F, 0x64, 0x75, 0x63, 0x74, 0x20, 0x73, 0x74, 0x72, 0x69, 0x6E, 0x67, 0x73, 0x2E,
0x56, 0x65, 0x6E, 0x64, 0x6F, 0x72, 0x20, 0x73, 0x74, 0x72, 0x69, 0x6E, 0x67, 0x73, 0x20, 0x61,
0x72, 0x65, 0x20, 0x70, 0x6C, 0x61, 0x63, 0x65, 0x64, 0x20, 0x68, 0x65, 0x72, 0x65, 0x2E, 0x20,
0x80,
0x7D,
0x0A, 0x93, 0x01
The data is stored beginning at address 0x00.
Vendor ID: 0x08BB
Device ID: 0x2704
Device string: Product strings. (16 bytes)
Vendor string: Vendor strings are placed here. (32 bytes, 31 visible characters are followed by 1 space)
bmAttribute: 0x80 (Bus-powered)
maxPower: 0x7D (250 mA)
Auxiliary HID usage ID: 0x0A, 0x93, 0x01 (AL A/V capture)
SERIAL PROGRAMMING INTERFACE (PCM2705/7)
The PCM2705/7 supports the serial programming interface (SPI) to program the descriptor and to set the HID state.
Descriptor data is described in the External ROM Descriptor section.
t
(MHH)
MS
50% of V
DD
t
t
(MCL)
(MLS)
t
t
(MLH)
(MCH)
MC
MD
50% of V
50% of V
DD
t
(MCY)
LSB
DD
t
(MDS)
t
(MDH)
SYMBOL
PARAMETERS
MIN
100
TYP
MAX UNITS
t
t
t
t
t
t
t
t
MC pulse cycle time
MC low-level time
MC high-level time
MS high-level time
ns
ns
ns
ns
ns
ns
ns
ns
(MCY)
(MCL)
(MCH)
(MHH)
(MLS)
(MLH)
(MDH)
(MDS)
50
50
100
20
MS falling edge to MC rising edge
MS hold time
20
MD hold time
15
MD setup time
20
Figure 26. SPI Timing Diagram
23
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