Vsb Pins - Renesas NU85E Preliminary User's Manual

2.2.2 VSB pins

(1) VAREQ (input)
This is the pin to which bus access right requests are input from an external bus master.
(2) VAACK (output)
This is an output pin for indicating that the bus access right request signal (VAREQ) from an external bus master
has been acknowledged.
(3) VAPREQ (output)
This pin outputs bus access right requests from the internal bus master (CPU, DMAC) to the external bus
master.
This pin is used when a bus master and a bus arbiter exist externally, to perform output to the external bus
arbiter. This pin becomes active (1) when a bus access right request is generated, and it becomes inactive (0)
when the bus cycle responding to the request has been generated. Its transition to active (1) during the CPU
cycle indicates that there is a request from the DMA, and its transition to active (1) during the DMA cycle
indicates that there is a request from the CPU.
(4) VBDI31 to VBDI0 (input)
These pins constitute a data input bus for macro connected to VSB.
(5) VBDO31 to VBDO0 (output)
These pins constitute a data output bus for macro connected to VSB.
(6) VMA27 to VMA0 (output), VSA13 to VSA0 (input)
These pins constitute an address bus for macro connected to VSB.
The NU85E uses the VMA27 to VMA0 pins when it has the bus access right, and the VSA13 to VSA0 pins when
it operates as a bus slave.
(7) VMTTYP1, VMTTYP0 (output)
These pins output the bus transfer type when the NU85E has the bus access right.
VMTTYP1 VMTTYP0
0
1
1
0
Remark 0: low-level 1: high-level
(8) VMSTZ (output), VSSTZ (input)
These are low-level active pins that indicate transfer start.
The NU85E uses the VMSTZ pin when it has the bus access right, and the VSSTZ pin when it operates as a bus
slave.
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CHAPTER 2 PIN FUNCTIONS
Table 2-1. VMTTYP1 and VMTTYP0 Signals
0 Address-only transfer (transfer without data processing)
0 Non-sequential transfer (single transfer or burst transfer)
1 Sequential transfer (transfer in which the address currently being
transferred is related to the previously transferred address)
1 (Reserved for future function expansion)
Preliminary User's Manual A14874EJ3V0UM
Transfer Type