RTSR vs RTTS Register Analysis - SINTRAN HDLC Usage¶

Register Distinction - Critical Understanding¶

SINTRAN HDLC uses two separate transmitter status registers:

RTSR (HDEV+6) - Read Transmitter Status Register¶

RTSR = 0006  % Basic HDLC transmitter status (IOX+6)

Purpose: Basic HDLC protocol status (flags, sync, etc.)
SINTRAN Usage: NOT used in main interrupt processing
Content: Traditional HDLC status bits

RTTS (HDEV+12) - Read Transmitter Transfer Status¶

RTTS = 0012  % DMA transmitter transfer status (IOX+12)

Purpose: DMA transfer status and completion information
SINTRAN Usage: PRIMARY register used in HOINT interrupt handler
Content: DMA status bits 8-15 + HDLC status bits 0-7

SINTRAN Interrupt Handler Usage¶

HOINT (Transmitter Interrupt) - Uses RTTS¶

HOINT: 0=:TMR                                % Reset timer
       T:=HDEV+RTTS; *EXR ST                 % IOX+12 - Read RTTS (NOT RTSR!)
       A=:HASTA                              % Store status

       IF A/\ "SILFO+TXUND" = 0 THEN         % Test DMA transfer success
          % Success processing
       ELSE  
          % Error/retry processing
       FI

Key Point: SINTRAN reads RTTS (HDEV+12) for transmission status, not RTSR (HDEV+6).

HIINT (Receiver Interrupt) - Uses RRTS¶

HIINT: T:=HDEV+RRTS; *EXR ST                % IOX+10 - Read receiver transfer status
       A=:HASTA                             % Store status

       IF A NBIT 0 OR A/\60000><0 THEN      % Test data available + X.21 errors
          GO OUT1                           % Drop packet
       FI

       CALL PROCPKT                         % Process packet

Key Point: SINTRAN reads RRTS (HDEV+10) for reception status.

Your C# Enum Analysis¶

Based on your enum comments mentioning "DMA MODULE" and "Bits 8-15 are cleared when reading", your enum is for RTTS/RRTS (transfer status registers), not RTSR (basic status register).

For Receiver (RRTS - HDEV+10):¶

// Your enum appears to be for RRTS (Receiver Transfer Status)
// SINTRAN validation for packet reception:

/// <summary>
/// DataAvailable (bit 0) - CRITICAL for packet processing
/// SINTRAN Logic: IF A NBIT 0 THEN GO OUT1 (drop packet)
/// Must be SET for packet to be processed
/// </summary>
DataAvailable = 1 << 0,

/// <summary>  
/// ListEmpty (bit 11) - CRITICAL system condition
/// SINTRAN Logic: IF HASTA/\"EMTY" >< 0 THEN 0=:ACTSW (shutdown receiver)
/// Setting this bit SHUTS DOWN the entire receiver
/// Only set if emulating buffer exhaustion
/// </summary>
ListEmpty = 1 << 11,

/// <summary>
/// X21D (bit 13) - X.21 protocol error
/// SINTRAN Logic: IF A/\ HX21M >< 0 THEN CALL X21ERR (protocol error)
/// Setting this triggers X.21 error handling
/// </summary>
X21D = 1 << 13,

/// <summary>
/// X21S (bit 14) - X.21 protocol error  
/// SINTRAN Logic: IF A/\ HX21M >< 0 THEN CALL X21ERR (protocol error)
/// Setting this triggers X.21 error handling
/// </summary>
X21S = 1 << 14

Register Map Summary¶

Register	Address	Name	SINTRAN Usage	Your Enum
RTSR	HDEV+6	Read Transmitter Status Register	Not used in interrupts	NO
RTTS	HDEV+12	Read Transmitter Transfer Status	Used in HOINT	YES (for transmit)
RRTS	HDEV+10	Read Receiver Transfer Status	Used in HIINT	YES (for receive)

Conclusion¶

Your C# enum is for RRTS/RTTS (DMA transfer status), not RTSR (basic status)
SINTRAN never uses RTSR (HDEV+6) in interrupt processing
SINTRAN uses RTTS (HDEV+12) for transmitter interrupts
SINTRAN uses RRTS (HDEV+10) for receiver interrupts
The confusion comes from the similar names - focus on RTTS/RRTS for DMA operations

For packet reception, you need to implement RRTS (HDEV+10) behavior, where setting DataAvailable (bit 0) indicates a packet is ready for processing.