R
Functional Description
D[7:0]
CCLK
+1.2V
+1.2V
VCCINT
VCCINT
P
HSWAP
VCCO_0
VCCO_0
VCCO_1
P
HSWAP
VCCO_0
VCCO_0
VCCO_1
VCCO_1
LDC0
LDC1
HDC
VCCO_1
LDC0
LDC1
HDC
Slave
Parallel
Mode
Slave
Parallel
Mode
LDC2
LDC2
VCCO_2
VCCO_2
V
V
V
V
‘1’
‘1’
‘0’
M2
M1
M0
‘1’
‘1’
‘0’
M2
M1
M0
Intelligent
Download Host
VCC
DATA[7:0]
BUSY
Spartan-3E
FPGA
Spartan-3E
FPGA
D[7:0]
BUSY
CSI_B
D[7:0]
BUSY
Configuration
Memory
Source
SELECT
READ/WRITE
CLOCK
CSO_B
INIT_B
CSI_B
CSO_B
INIT_B
CSO_B
‘0’
RDWR_B
CCLK
‘0’
RDWR_B
CCLK
•Internal memory
•Disk drive
PROG_B
DONE
•Over network
•Over RF link
VCCAUX
TDO
+2.5V
VCCAUX
TDO
+2.5V
INIT_B
TDI
TDI
TMS
TCK
TMS
TCK
GND
+2.5V
•Microcontroller
•Processor
•Tester
PROG_B
DONE
PROG_B
DONE
GND
GND
PROG_B
PROG_B
DONE
Recommend
open-drain
driver
2.5V
JTAG
INIT_B
TDI
TMS
TCK
TDO
TMS
TCK
DS312-2_53_022305
Figure 59: Daisy-Chaining using Slave Parallel Mode
indicating that the FPGA is ready to receive its first data.
The host then continues supplying data and clock signals
until either the DONE pin goes High, indicating a successful
configuration, or until the INIT_B pin goes Low, indicating a
configuration error. The configuration process requires
more clock cycles than indicated from the configuration file
size. Additional clocks are required during the FPGA’s
start-up sequence, especially if the FPGA is programmed to
wait for selected Digital Clock Managers (DCMs) to lock to
their respective clock inputs (see Start-Up, page 91).
Slave Serial Mode
In Slave Serial mode (M[2:0] = <1:1:1>), an external host
such as a microprocessor or microcontroller writes serial
configuration data into the FPGA, using the synchronous
serial interface shown in Figure 60. The serial configuration
data is presented on the FPGA’s DIN input pin with suffi-
cient setup time before each rising edge of the externally
generated CCLK clock input.
The intelligent host starts the configuration process by puls-
ing PROG_B and monitoring that the INIT_B pin goes High,
DS312-2 (v1.1) March 21, 2005
www.xilinx.com
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Advance Product Specification
XILINX [ XILINX, INC ]
