diff --git a/src/app/registers/RegisterBrowser.tsx b/src/app/registers/RegisterBrowser.tsx
index 47cc47d..4d74ac1 100644
--- a/src/app/registers/RegisterBrowser.tsx
+++ b/src/app/registers/RegisterBrowser.tsx
@@ -74,12 +74,6 @@ export default function RegisterBrowser({ registers }: RegisterBrowserProps) {
     register.description.toLowerCase().includes(searchTerm.toLowerCase())
   );
 
-  const getDefaultActiveKey = (register: Register) => {
-    if (register.common) return 'common';
-    if (register.read) return 'read';
-    if (register.write) return 'write';
-    return '';
-  };
 
   return (
     <Container fluid>
@@ -92,12 +86,9 @@ export default function RegisterBrowser({ registers }: RegisterBrowserProps) {
         />
       </Form.Group>
       <Row>
-        {filteredRegisters.map(register => {
-          const defaultActiveKey = getDefaultActiveKey(register);
-          return (
-              <RegisterDetail key={register.hex_address} register={register} defaultActiveKey={defaultActiveKey} />
-          );
-        })}
+        {filteredRegisters.map(register => (
+              <RegisterDetail key={register.hex_address} register={register} />
+        ))}
       </Row>
     </Container>
   );
diff --git a/src/app/registers/RegisterDetail.tsx b/src/app/registers/RegisterDetail.tsx
index 443daf4..b32c22a 100644
--- a/src/app/registers/RegisterDetail.tsx
+++ b/src/app/registers/RegisterDetail.tsx
@@ -10,15 +10,12 @@ import * as Icon from 'react-bootstrap-icons';
 /**
  * A client-side component that displays the details of a single register.
  * @param register The register object to display.
- * @param defaultActiveKey The default active tab to display.
  * @returns A React component that displays the register details.
  */
 export default function RegisterDetail({
   register,
-  defaultActiveKey,
 }: {
   register: Register;
-  defaultActiveKey?: string;
 }) {
   const [showSource, setShowSource] = useState(false);
 
@@ -27,9 +24,7 @@ export default function RegisterDetail({
         <Card>
           <Card.Header>
             <code>{register.hex_address}</code> ( {register.dec_address} ) &nbsp;
-            {/*<Link href={`https://wiki.specnext.dev/${encodeURIComponent((register.name).replace(' ','_'))}_Register`} className="text-decoration-none">*/}
               <strong>{register.name}</strong> {register.issue_4_only && <span className="badge bg-danger">Issue 4 Only</span>}
-            {/*</Link>*/}
             <div className="float-end small text-muted">
               <Link href={`https://wiki.specnext.dev/${encodeURIComponent((register.name).replace(' ','_'))}_Register`} className="text-decoration-none btn btn-sm btn-primary" title="Open wiki">
                 <Icon.Wikipedia />
@@ -45,20 +40,27 @@ export default function RegisterDetail({
             </div>
           </Card.Header>
           <Card.Body>
-            <Tabs defaultActiveKey={defaultActiveKey} id={`register-tabs-${register.hex_address}`}>
-              {register.common && <Tab eventKey="common" title="Read/Write">{renderAccess(register.common)}</Tab>}
-              {register.read && <Tab eventKey="read" title="Read">{renderAccess(register.read)}</Tab>}
-              {register.write && <Tab eventKey="write" title="Write">{renderAccess(register.write)}</Tab>}
-            </Tabs>
-            {register.notes.map((note, index) => (
-                <p key={index} className="small text-muted">{note.ref} {note.text}</p>
+            { register.modes.map((mode, idx) => (
+              <div key={idx} className={idx > 0 ? 'mt-4' : ''}>
+                {register.modes.length > 1 && (
+                  <h5 className="mb-3">Mode {idx + 1}</h5>
+                )}
+                <Tabs id={`register-tabs-${register.hex_address}-${idx}`}>
+                  {mode.common && <Tab eventKey="common" title="Read/Write">{renderAccess(mode.common)}</Tab>}
+                  {mode.read && <Tab eventKey="read" title="Read">{renderAccess(mode.read)}</Tab>}
+                  {mode.write && <Tab eventKey="write" title="Write">{renderAccess(mode.write)}</Tab>}
+                </Tabs>
+                {mode.notes && mode.notes.map((note, index) => (
+                  <p key={index} className="small text-muted">{note.ref} {note.text}</p>
+                ))}
+                {mode.text && mode.text.length > 0 && (
+                  <div className="mt-3">
+                    <h6>Notes:</h6>
+                    <pre>{mode.text}</pre>
+                  </div>
+                )}
+              </div>
             ))}
-            {register.text && register.text.length > 0 && (
-                <div className="mt-3">
-                  <h5>Notes:</h5>
-                  <pre>{register.text}</pre>
-                </div>
-            )}
           </Card.Body>
         </Card>
 
diff --git a/src/app/registers/[hex]/page.tsx b/src/app/registers/[hex]/page.tsx
index 635f0e4..0622dcb 100644
--- a/src/app/registers/[hex]/page.tsx
+++ b/src/app/registers/[hex]/page.tsx
@@ -13,7 +13,6 @@ export default async function RegisterDetailPage({ params }: { params: { hex: st
 
     if (!register) return notFound();
 
-    const defaultActiveKey = register.common ? 'common' : (register.read ? 'read' : (register.write ? 'write' : undefined));
 
     return (
         <Container fluid className="py-4">
@@ -21,7 +20,7 @@ export default async function RegisterDetailPage({ params }: { params: { hex: st
                 <Link href="/registers" className="btn btn-secondary">← Back to Registers</Link>
             </div>
             <Row>
-                <RegisterDetail register={register} defaultActiveKey={defaultActiveKey} />
+                <RegisterDetail register={register} />
             </Row>
         </Container>
     );
diff --git a/src/utils/register_parser.ts b/src/utils/register_parser.ts
index 0e83084..da49f35 100644
--- a/src/utils/register_parser.ts
+++ b/src/utils/register_parser.ts
@@ -18,16 +18,21 @@ export interface RegisterAccess {
   operations: RegisterBitwiseOperation[];
   notes: Note[];
 }
-export interface Register {
-  hex_address: string;
-  dec_address: number | string;
-  name: string;
-  description: string;
+
+export interface RegisterDetail {
   read?: RegisterAccess;
   write?: RegisterAccess;
   common?: RegisterAccess;
   text: string;
   notes: Note[];
+}
+
+export interface Register {
+  hex_address: string;
+  dec_address: number | string;
+  name: string;
+  modes: RegisterDetail[];
+  description: string;
   issue_4_only: boolean;
   source: string[];
 }
@@ -84,8 +89,7 @@ export function processRegisterBlock(paragraph: string, registers: Register[]) {
       dec_address: dec,
       name: regName,
       description: description,
-      notes: [],
-      text: "",
+      modes: [],
       issue_4_only: false,
       source: []
     };
diff --git a/src/utils/register_parsers/reg_default.ts b/src/utils/register_parsers/reg_default.ts
index 42713fc..4ebb55f 100644
--- a/src/utils/register_parsers/reg_default.ts
+++ b/src/utils/register_parsers/reg_default.ts
@@ -1,9 +1,11 @@
-import {Register, RegisterAccess} from "@/utils/register_parser";
+import {Register, RegisterAccess, RegisterDetail} from "@/utils/register_parser";
 
 export const parseDescriptionDefault = (reg: Register, description: string) => {
     const descriptionLines = description.split('\n');
     let currentAccess: 'read' | 'write' | 'common' | null = null;
     let accessData: RegisterAccess = { operations: [], notes: [] };
+    // Prepare a new RegisterDetail for this description block
+    const detail: RegisterDetail = { read: undefined, write: undefined, common: undefined, text: '', notes: [] };
 
     for (const line of descriptionLines) {
         if (line.includes('Issue 4 Only')) reg.issue_4_only = true;
@@ -14,25 +16,34 @@ export const parseDescriptionDefault = (reg: Register, description: string) => {
         if (trimmedLine.startsWith('//')) continue;
 
         if (trimmedLine.startsWith('(R)')) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) {
+                // finalize previous access block into detail
+                detail[currentAccess] = accessData;
+            }
             accessData = { operations: [], notes: [] };
             currentAccess = 'read';
             continue;
         }
         if (trimmedLine.startsWith('(W)')) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) {
+                detail[currentAccess] = accessData;
+            }
             accessData = { operations: [], notes: [] };
             currentAccess = 'write';
             continue;
         }
         if (trimmedLine.startsWith('(R/W')) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) {
+                detail[currentAccess] = accessData;
+            }
             accessData = { operations: [], notes: [] };
             currentAccess = 'common';
             continue;
         }
         if (line.startsWith(trimmedLine)) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) {
+                detail[currentAccess] = accessData;
+            }
             accessData = { operations: [], notes: [] };
             currentAccess = null;
         }
@@ -81,17 +92,20 @@ export const parseDescriptionDefault = (reg: Register, description: string) => {
             if (trimmedLine.startsWith('*')) {
                 const noteMatch = trimmedLine.match(/^(\*+)\s*(.*)/);
                 if (noteMatch) {
-                    reg.notes.push({
+                    detail.notes.push({
                         ref: noteMatch[1],
                         text: noteMatch[2],
                     });
                 }
             } else if (trimmedLine) {
-                reg.text += `${line}\n`;
+                detail.text += `${line}\n`;
             }
         }
     }
     if (currentAccess) {
-        reg[currentAccess] = accessData;
+        detail[currentAccess] = accessData;
     }
+    // Push the parsed detail into modes
+    reg.modes = reg.modes || [];
+    reg.modes.push(detail);
 };
\ No newline at end of file
diff --git a/src/utils/register_parsers/reg_f0.ts b/src/utils/register_parsers/reg_f0.ts
index 8bca351..1c7a68a 100644
--- a/src/utils/register_parsers/reg_f0.ts
+++ b/src/utils/register_parsers/reg_f0.ts
@@ -1,12 +1,13 @@
 
 // Special-case parser for 0xF0 (XDEV CMD): treat headings beginning with '*' inside access blocks
 // as descriptive text instead of notes, so sub-modes become part of the section descriptions.
-import {Register, RegisterAccess} from "@/utils/register_parser";
+import {Register, RegisterAccess, RegisterDetail} from "@/utils/register_parser";
 
 export const parseDescriptionF0 = (reg: Register, description: string) => {
     const descriptionLines = description.split('\n');
     let currentAccess: 'read' | 'write' | 'common' | null = null;
     let accessData: RegisterAccess = { operations: [], notes: [] };
+    const detail: RegisterDetail = { read: undefined, write: undefined, common: undefined, text: '', notes: [] };
 
     for (const line of descriptionLines) {
         if (line.includes('Issue 4 Only')) reg.issue_4_only = true;
@@ -17,25 +18,25 @@ export const parseDescriptionF0 = (reg: Register, description: string) => {
         if (trimmedLine.startsWith('//')) continue;
 
         if (trimmedLine.startsWith('(R)')) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) detail[currentAccess] = accessData;
             accessData = { operations: [], notes: [] };
             currentAccess = 'read';
             continue;
         }
         if (trimmedLine.startsWith('(W)')) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) detail[currentAccess] = accessData;
             accessData = { operations: [], notes: [] };
             currentAccess = 'write';
             continue;
         }
         if (trimmedLine.startsWith('(R/W')) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) detail[currentAccess] = accessData;
             accessData = { operations: [], notes: [] };
             currentAccess = 'common';
             continue;
         }
         if (line.startsWith(trimmedLine)) {
-            if (currentAccess) reg[currentAccess] = accessData;
+            if (currentAccess) detail[currentAccess] = accessData;
             accessData = { operations: [], notes: [] };
             currentAccess = null;
         }
@@ -79,20 +80,22 @@ export const parseDescriptionF0 = (reg: Register, description: string) => {
             }
         } else {
             if (trimmedLine.startsWith('*')) {
-                // Outside access blocks, keep notes as-is
+                // Outside access blocks, keep notes as-is but attach to detail now
                 const noteMatch = trimmedLine.match(/^(\*+)\s*(.*)/);
                 if (noteMatch) {
-                    reg.notes.push({
+                    detail.notes.push({
                         ref: noteMatch[1],
                         text: noteMatch[2],
                     });
                 }
             } else if (trimmedLine) {
-                reg.text += `${line}\n`;
+                detail.text += `${line}\n`;
             }
         }
     }
     if (currentAccess) {
-        reg[currentAccess] = accessData;
+        detail[currentAccess] = accessData;
     }
+    reg.modes = reg.modes || [];
+    reg.modes.push(detail);
 };