II CORE BLOCK: BCU (Bus Control Unit)
User interface signals
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| Table 4.2 List of User Interface Signals |
Signal name | I/O | Function |
Internal_addr0 | O | • Address bus (a0) when SBUSST(D3/0x4812E) = "0" (default) |
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| • Bus strobe (low byte) signal (#BSL) when SBUSST(D3/0x4812E) = "1" |
Internal_addr[23:1] | O | Address bus (a1 to a23) |
Internal_dout[15:0] | O | Output data bus (dout0 to dout15) |
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| This data bus is used when the CPU writes data to the |
Internal_din[15:0] | I | Input data bus (din0 to din15) |
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| This data bus is used when the CPU reads data from the |
Internal_ce4_x | O | Areas |
Internal_ce5_x |
| These signals go low when the CPU accesses the user logic circuits that are mapped to Areas |
Internal_ce6_x |
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Internal_rd_x | O | Read signal |
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| This signal goes low when the CPU reads data from the user logic. |
Internal_wrl_x | O | • Write (low byte) signal (#WRL) when SBUSST(D3/0x4812E) = "0" (default) |
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| • Write signal (#WR) when SBUSST(D3/0x4812E) = "1" |
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| This signal goes low when the CPU write 8 |
Internal_wrh_x | O | • Write (high byte) signal (#WRH) when SBUSST(D3/0x4812E) = "0" (default) |
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| • Bus strobe (high byte) signal (#BSH) when SBUSST(D3/0x4812E) = "1" |
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| This signal goes low when the CPU write 8 |
Internal_osc3_clk | O | |
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| This can be used as a source clock for the user logic. |
Internal_pll_clk | O | PLL output clock |
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| This can be used as a source clock for the user logic. |
Internal_wait_x | I | Wait cycle request input |
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| The user logic can request to insert wait cycles by setting this signal to low. |
Internal_irrd_x | O | Instruction fetch indicator signal |
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| This signal goes low when the CPU is in an instruction fetch cycle. |
I | Input signals | |
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| These signals are connected to the input ports |
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| interrupts using these signals. The user logic can also be used as input ports with these signals. |
The internal bus signals are available when an internal access area is set using the BCU register. The bus conditions can be programmed using the BCU registers similar to the external bus.
EPSON | S1C33L03 FUNCTION PART |