[Doc] Update I/O arrangement to be consistent with new arch

This commit is contained in:
tangxifan 2020-11-17 20:45:20 -07:00
parent 58440b8c42
commit 2b0c5c67e9
5 changed files with 8 additions and 6 deletions

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@ -12,11 +12,11 @@ The *High-Density* (HD) FPGA IP has 144 I/O pins as shown in :numref:`fig_fpga_i
Among the 144 I/Os,
- **30 external I/Os** are accessible through the Caravel SoC's *General-Purpose I/Os* (GPIOs).
- **29 external I/Os** are accessible through the Caravel SoC's *General-Purpose I/Os* (GPIOs).
- **114 internal I/Os** are accessible through the Caravel SOC's logic analyzer and wishbone interfaces, which are controlled by the RISC-V processor. See :ref:`io_resource_debug` and :ref:`io_resource_accelerator` for details.
- **115 internal I/Os** are accessible through the Caravel SOC's logic analyzer and wishbone interfaces, which are controlled by the RISC-V processor. See :ref:`io_resource_debug` and :ref:`io_resource_accelerator` for details.
.. note:: The connectivity of the 114 internal I/Os can be switched through a GPIO of Caravel SoC. As a result, the FPGA can operate in different modes.
.. note:: The connectivity of the 115 internal I/Os can be switched through a GPIO of Caravel SoC. As a result, the FPGA can operate in different modes.
.. _fig_fpga_io_switch:
@ -35,7 +35,7 @@ Accelerator Mode
When the Wishbone interface is enabled, the FPGA can operate as an accelerator for the RISC-V processor.
:numref:`fig_fpga_io_map_wishbone_mode` illustrates the detailed I/O arrangement for the FPGA, where the wishbone bus signals are connected to fixed FPGA I/O locations.
.. note:: Not all the 114 internal I/Os are used by the Wishbone interface. Especially, the I/O[122:131] are not connected.
.. note:: Not all the 115 internal I/Os are used by the Wishbone interface. Especially, the I/O[122:131] are not connected.
.. warning:: The FPGA does not contain a Wishbone slave IP. Users have to implement a soft Wishbone slave when use the FPGA as an accelerator.
@ -55,7 +55,7 @@ Debug Mode
When the logic analyzer interface is enabled, the FPGA can operate in debug mode, whose internal signals can be readback through the registers of the RISC-V processor.
:numref:`fig_fpga_io_map_logic_analyzer_mode` illustrates the detailed I/O arrangement for the FPGA, where the logic analyzer signals are connected to fixed FPGA I/O locations.
.. note:: The logic analyzer is 128-bit, while 114 bits can drive or be driven by the FPGA I/O. The other 14 bits are connected to internal spots of the FPGA fabric, monitoring critical signal activities of the FPGA in debugging purpose.
.. note:: The logic analyzer is 128-bit, while 115 bits can drive or be driven by the FPGA I/O. The other 14 bits are connected to internal spots of the FPGA fabric, monitoring critical signal activities of the FPGA in debugging purpose.
.. _fig_fpga_io_map_logic_analyzer_mode:

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@ -13,7 +13,7 @@ I/O usage and port information
+-----------+------------------------------------------------------------------------+-------------+
| I/O Type | Description | No. of Pins |
+===========+========================================================================+=============+
| Data I/O | Datapath I/Os of FPGA fabric | 30 |
| Data I/O | Datapath I/Os of FPGA fabric | 29 |
+-----------+------------------------------------------------------------------------+-------------+
| Clk | Operating clock of FPGA core | 1 |
+-----------+------------------------------------------------------------------------+-------------+
@ -29,6 +29,8 @@ I/O usage and port information
+-----------+------------------------------------------------------------------------+-------------+
| SCout | Output of built-in scan-chain to read back flip-flops from FPGA fabric | 1 |
+-----------+------------------------------------------------------------------------+-------------+
| IO_ISLO_N | Active-low signal to enable I/O datapath isolation from external ports | 1 |
+-----------+------------------------------------------------------------------------+-------------+
| Total | | 37 |
+-----------+------------------------------------------------------------------------+-------------+