Page 20
Functional Description
The controller chip features a programmable oscillator that can output four different
frequencies. The various settings generate clock outputs at frequencies as high as 10,
33, 50, and 66 MHz. Tab le 7 lists the internal oscillator frequencies.
Table 7. Internal Oscillator Frequencies
Frequency Setting
Min (MHz)
6.4
Typ (MHz)
8.0
Max (MHz)
10.0
10
33
50
66
21.0
26.5
33.0
32.0
40.0
50.0
42.0
53.0
66.0
Clock source, oscillator frequency, and clock divider (N) settings can be made in the
Quartus II software, by accessing the Configuration Device Options inside the
Device Settings window or the Convert Programming Files window. The same
window can be used to select between the internal oscillator and the external clock
(EXCLK)input pin as your configuration clock source. The default setting selects the
internal oscillator at the 10 MHz setting as the clock source, with a divide factor of 1.
f For more information about making the configuration clock source, frequency, and
divider settings, refer to the Altera Enhanced Configuration Devices.
Flash In-System Programming (ISP)
The flash memory inside EPC devices can be programmed in-system using the JTAG
interface and the external flash interface. JTAG-based programming is facilitated by
the configuration controller in the EPC device. External flash interface programming
requires an external processor or FPGA to control the flash.
1
The EPC device flash memory supports 100,000 erase cycles.
JTAG-based Programming
The IEEE Std. 1149.1 JTAG Boundary Scan is implemented in EPC devices to facilitate
the testing of its interconnection and functionality. EPC devices also support the ISP
mode. The EPC device is compliant with the IEEE Std. 1532 draft 2.0 specification.
The JTAG unit of the configuration controller communicates directly with the flash
memory. The controller processes the ISP instructions and performs the necessary
flash operations. EPC devices support the maximum JTAG TCKfrequency of 10 MHz.
During JTAG-based ISP, the external flash interface is not available. Before the JTAG
interface programs the flash memory, an optional JTAG instruction (PENDCFG) can be
used to assert the FPGA’s nCONFIGpin (using the nINIT_CONFpin). This will keep the
FPGA in reset and terminate any internal flash access. This function prevents
contention on the flash pins when both JTAG ISP and an external FPGA or processor
try to access the flash simultaneously. The nINIT_CONFpin is released when the initiate
configuration (nINIT CONF) JTAG instruction is updated. As a result, the FPGA is
_
configured with the new configuration data stored in flash.
You can add an initiate configuration (nINIT_CONF) JTAG instruction to your
programming file in the Quartus II software by enabling the Initiate configuration
after programming option in the Programmer options window (Options menu).
Enhanced Configuration (EPC) Devices Datasheet
January 2012 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
