AN2131SC Cypress Semiconductor Corp, AN2131SC Datasheet - Page 160

• Manufacturer Part Number: AN2131SC
• Description: IC MCU 8051 8K RAM 24MHZ 44QFP
• Manufacturer: Cypress Semiconductor Corp
• Series: EZ-USB®r

Specifications of AN2131SC

• Applications: USB Microcontroller
• Core Processor: 8051
• Program Memory Type: ROMless
• Controller Series: AN213x
• Ram Size: 8K x 8
• Interface: I²C, USB
• Number Of I /o: 16
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1306; AN2131SC

times 19 cycles, or 2,432 cycles. The 1,024 byte transfer would take 403 s, less than
half of the 1-ms USB frame time.
If still faster time is required, the routine can be modified to put more of the MOVX
instructions in-line. For example, with 16 in-line MOVX instructions, the transfer time
for 1,024 bytes would be 35 cycles times 64 loops or 2,240 cycles, or 371 s, an 8% speed
improvement over the eight instruction loop.
Two additional registers, ISOCTL and ZBCOUT, provide additional isochronous endpoint
features.
8.9.1 Disable ISO
Bit zero of the ISOCTL register is called ISODISAB. When the 8051 sets ISODISAB=1,
all sixteen of EZ-USB endpoints are disabled. If ISODISAB=1, EP8IN=EP15IN and
EP8OUT-EP15OUT should not be used. ISODISAB is cleared at power-on.
When ISODISAB=1, the 2,048 bytes of RAM normally used for isochronous buffers is
available to the 8051 as XDATA RAM (not program memory), from 0x2000 to 0x27FF in
internal memory. When ISODISAB=1, the behavior of the RD# and WR# strobe signals
changes to reflect the additional 2 KB of memory inside the EZ-USB chip. This is shown
in Table 8-2.
EZ-USB TRM v1.9
ISOCTL
8.9
b7
-
Other Isochronous Registers
b6
-
Table 8-2. Addresses for RD# and WR# vs. ISODISAB bit
b5
-
Figure 8-14. ISOCTL Register
Isochronous Control
Chapter 8. EZ-USB CPU
ISODISAB
(default)
b4
-
0
1
2000-7B40,
8000-FFFF
2800-7B40,
8000-FFFF
RD#, WR#
PPSTAT
b3
MBZ
b2
MBZ
b1
ISODISAB
Page 8-15
b0
7FA1