◆Result parameter details

●Peripheral control status

SMPC outputs peripheral control status to the status register (SR) when using SMPC control mode. The status register (SR) is a register that can be read regardless of the INTBACK command. However, even if this register is read while the INTBACK command is not in use, other than the RESB bit is undefined.

Figure 3.13 Peripheral control status

bit7	bit6	bit5	bit4	bit3	bit2	bit1	bit0
1	PDL	NPE	RESB	P2MD1	P2MD0	P1MD1	P1MD0

P1MD: Port 1 mode

00:15 byte mode (returns peripheral data up to 15 bytes)

01:255 byte mode (returns peripheral data up to 255 bytes)

10: Not used (setting prohibited)

11:0 byte mode (does not access ports)

P2MD: Port 2 mode

00:15 byte mode (returns peripheral data up to 15 bytes)

01:255 byte mode (returns peripheral data up to 255 bytes)

10: Not used (setting prohibited)

11:0 byte mode (does not access ports)

RESB: Reset button status bit

0: Reset button OFF

1: Reset button ON

It can be read regardless of the INTBACK command. (Displays the status of each V-BLANK-IN)

NPE: Remaining peripheral data presence/absence bit

0: No data remaining

1: Remaining data available

PDL: Peripheral data position bit

Peripheral data after 0:2nd

1:1st peripheral data

bit7

It is always 1.

●Port status

Port status is 1 byte of data that indicates the status of peripherals connected to the port. By using the port status, you can determine whether a peripheral is directly connected to the corresponding port, how many multi-tap taps are connected, etc. Figure 3.14 shows the port status configuration.

Figure 3.14 Port status configuration

bit7	bit6	bit5	bit4	bit3	bit2	bit1	bit0
Multi-tap ID				Number of connectors

Number of connectors

If a peripheral is directly connected to a peripheral port, the number of connectors will indicate 1H, indicating that one peripheral is connected to the corresponding port. If a multitap is connected, it shows the number of taps for that multitap. Indicates 0H when nothing is connected to the peripheral port or when a peripheral that cannot be recognized by SMPC is connected to the peripheral port.
Table 3.5 shows the relationship between the number of connectors and connected peripherals.

Table 3.5 Relationship between number of connectors and peripherals

Number of connectors	connected peripherals
0H	・Not connected ・ SMPC UNKOWN peripherals are connected
1H	・Directly connected peripherals
2H～FH	・Number of multi-tap taps

Multi tap ID

Multi-tap IDs are classified as follows depending on the peripherals connected.

1. The multitap ID indicates FH when the peripheral is directly connected to the peripheral port and when the peripheral is unconnected.

2. When a multi-tap is connected to the peripheral port, it indicates 0H to EH.

3. When a device that SMPC cannot recognize (UNKNOWN device) is connected to the peripheral port, the Mega Drive Peripheral ID (MD PID) is displayed.

SMPC UNKNOWN device connection is determined by receiving an MD PID that SMPC does not support during the initial phase between SMPC and the peripheral. When using Justifier (Lethal Enforcers' gun), etc., you can perform connection judgment in SMPC control mode, obtain the port status, and then use SH2 direct mode. Also, when a line error occurs during the initial phase between the SMPC and the peripheral, it may be determined as UNKNOWN.

Table 3.6 Relationship between connected peripherals and multitap ID

connected to peripheral port peripheral	Data indicated by multi-tap ID
Peripherals directly connected, not connected	FH
multi tap connection	0H～EH
UNKNOWN device connection	MD-PID

Multitap IDs are collected separately from Saturn Peripheral IDs. Multitap ID is provided as a multitap specification.
Table 3.7 shows the currently supported multi-tap IDs and number of connectors.

Table 3.7 Multi-tap ID and number of connectors

Multi tap name	Multi tap ID	Number of connectors
sega tap	0H	4H
Sega Saturn 6P Multitap	1H	6H
sega reservation	2H～EH	-