Yamaha OPL3-SA3 Download Resource data, External EEPROM, Hardware Volume Control, YMF715E

YMF715E

3. Download Resource data

When OPL3-SA3 is in the Configuration state, the host can download the resources data to EEPROM and internal SRAM via 20h: Resource Data Write. To switch OPL3-SA3 into configuration mode, there are two methods.

First method is to use the normal PnP protocol. After CSN was assigned for all ISA cards by PnP soft- ware, get CSN from CM (configuration manager) and write the CSN to Wake [CSN], then OPL3-SA3 switches into configuration state.

Second method is to use the YAMAHA Key sequence which is described in the Manual Configuration mode section. After OPL3-SA3 detects YAMAHA key, OPL3-SA3 switches into the Sleep state. Writing “81h” to Wake [CSN] register changes OPL3-SA3 into Configuration state.

After OPL3-SA3 switches into the Configuration state, download the Resource data to EEPROM and internal SRAM by using following sequence.

1.Write “01h”(RDWE bit = “1”) to 21h: Resource Data Write Enable register to reset internal address counter and to enable downloading the data.

2.Write Resource data to 20h: Resource Data Write register until downloading data is completed.

3.Write “00h” to 21h: Resource Data Write Enable register to disable downloading .

4.External EEPROM

The resource data information of OPL3-SA3 used for PnP auto configuration is stored in external EEPROM. And either 256 x 16-bit EEPROM or 128 x 16-bit EEPROM, such as 93C55, 93C56, 93C65, 93C66 should be used.

5. Hardware Volume Control

5-1. Hardware Volume up/down/mute Control

Two digital input pins; /VOLUP and /VOLDW can control the master volume of OPL3-SA3.

When /VOLUP is low level, register value of master volume is decremented(-1). When the value reaches to “00h”(max.0dB), the input signal will not be effective.

When /VOLDW is low level, register value of master volume is incremented(+1). When the value reaches to “0Fh”(min.-30dB), the input signal will not be effective.

When both of the /VOLUP and /VOLDW are low level simultaneously, volume is muted. When either /VOLUP or /VOLDW is low level, the previous value becomes effective, and volume is no mute.

5-2. Hardware Volume Interrupt

If configured VEN(Hardware Volume Enable)=1, SA3 Control Register, index 0Ah, D7 bit, when one of the hardware volume control pins /VOLUP or /VOLDW is asserted or when both are asserted to request mute, interrupt will be posted in the interrupt channel specified in SA3 Control Register, index 17h, IRQ-A MV or IRQ-B MV bit.

Note that when the muting is in effect, the subsequent mute requests which does not change any register contents will generate interrrupts. The ignored UP/DOWN requests (UP requests with 0dB Volume attn., DOWN requests with -30dB) will not generate interrupts.

This bit is cleared upon host’s reading the Master Volume Lch register, SA3 Control Register, index 07h.

May 21, 1997

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